C-mip interacts with the p85 subunit of PI3 kinase and exerts a dual effect on ERK signaling via the recruitment of Dip1 and DAP kinase

In naive T cells, Lck exerts a negative control on the ERK/MAPK pathway. We show that c-mip (c-maf inducing protein) interacts with the p85 subunit of PI3 kinase and inactivates Lck, which results in Erk1/2 and p38 MAPK activation. This effect is not enough to activate AP1 given the inability of ERK to migrate into the nucleus and to transactivate its target genes. We demonstrate that c-mip interacts with Dip1 and upregulates DAPK, which blocks the nuclear translocation of ERK1/2. This dual effect of c-mip is unique and might represent a potential mechanism to prevent the development of an immune response.

Structured summary

MINT-7383650: p85 (uniprotkb:P27986) physically interacts (MI:0915) with c-Mip (uniprotkb:Q8IY22) by anti bait coimmunoprecipitation (MI:0006)MINT-7383661: c-Mip (uniprotkb:Q8IY22) physically interacts (MI:0915) with p85 (uniprotkb:P27986) by anti tag coimmunoprecipitation (MI:0007)MINT-7383676: p85 (uniprotkb:P27986) physically interacts (MI:0915) with p110 (uniprotkb:P42336) by anti bait coimmunoprecipitation (MI:0006)MINT-7383689, MINT-7383711: Dip-1 (uniprotkb:Q80SY4) physically interacts (MI:0915) with c-Mip (uniprotkb:Q8IY22) by anti tag coimmunoprecipitation (MI:0007)     

BS69 cooperates with TRAF3 in the regulation of Epstein-Barr virus-derived LMP1/CTAR1-induced NF-κB activation

Epstein-Barr virus latent membrane protein 1 (LMP1) activates NF-κB signaling pathways through two C-terminal regions, CTAR1 and CTAR2. Previous studies have demonstrated that BS69, a multidomain cellular protein, regulates LMP1/CTAR2-mediated NF-κB activation by interfering with the complex formation between TRADD and LMP1/CTAR2. Here, we found that BS69 directly interacted with the LMP1/CTAR1 domain and regulated LMP1/CTAR1-mediated NF-κB activation and subsequent IL-6 production. Regarding the mechanisms involved, we found that BS69 directly interacted with TRAF3, a negative regulator of NF-κB activation. Furthermore, small-interfering RNA-mediated knockdown experiments revealed that TRAF3 was involved in the BS69-mediated suppression of LMP1/CTAR1-induced NF-κB activation.

Structured summary

MINT-7556591: lmp1 (uniprotkb:P03230) physically interacts (MI:0915) with BS69 (uniprotkb:Q15326) by anti tag coimmunoprecipitation (MI:0007)MINT-7556646: TRAF6 (uniprotkb:Q9Y4K3) physically interacts (MI:0915) with BS69 (uniprotkb:Q15326) by anti tag coimmunoprecipitation (MI:0007)MINT-7556658, MINT-7556670: TRAF3 (uniprotkb:Q13114) physically interacts (MI:0915) with BS69 (uniprotkb:Q15326) by anti tag coimmunoprecipitation (MI:0007)MINT-7556607: TRAF1 (uniprotkb:Q13077) physically interacts (MI:0915) with BS69 (uniprotkb:Q15326) by anti tag coimmunoprecipitation (MI:0007)MINT-7556634: TRAF5 (uniprotkb:O00463) physically interacts (MI:0915) with BS69 (uniprotkb:Q15326) by anti tag coimmunoprecipitation (MI:0007)MINT-7556622: TRAF2 (uniprotkb:Q12933) physically interacts (MI:0915) with BS69 (uniprotkb:Q15326) by anti tag coimmunoprecipitation (MI:0007)     

p53 inhibits tumor cell invasion via the degradation of snail protein in hepatocellular carcinoma

The tumor suppressor protein p53 is a key regulator of cell cycle arrest and apoptosis. Snail protein regulates cancer-associated malignancies. However, the relationship between p53 and Snail proteins in hepatocellular carcinoma (HCC) has not been completely understood. To determine whether Snail and p53 contribute to hepatocarcinogenesis, we analyzed the expression of Snail proteins in p53-overexpressing HCC cells. We found that p53 wild-type (WT) induced the degradation of Snail protein via murine double minute 2-mediated ubiquitination, whereas p53 mutant did not induce Snail degradation. As we expected, only p53WT induced endogenous Snail protein degradation and inhibited tumor cell invasion. These findings contribute to a better understanding of the role of p53 mutation and Snail overexpression as a late event in hepatocarcinogenesis.

Structured summary

MINT-7718917: p53 (uniprotkb:P04637) physically interacts (MI:0915) with Snai1 (uniprotkb:O95863) by anti bait coimmunoprecipitation (MI:0006)MINT-7719877: Snai1 (uniprotkb:O95863) physically interacts (MI:0915) with ubiquitin (uniprotkb:P62988) by anti tag coimmunoprecipitation (MI:0007)MINT-7718928: Snai1 (uniprotkb:O95863) physically interacts (MI:0915) with p53 (uniprotkb:P04637) by anti tag coimmunoprecipitation (MI:0007)MINT-7718939: Snai1 (uniprotkb:O95863) physically interacts (MI:0915) with MDM2 (uniprotkb:Q00987) by anti tag coimmunoprecipitation (MI:0007)     

ARF-dependent regulation of ATM and p53 associated KZNF (Apak) protein activity in response to oncogenic stress

The KRAB-type zinc-finger protein Apak (ATM and p53 associated KZNF protein) specifically suppresses p53-mediated apoptosis. Upon DNA damage, Apak is phosphorylated and inhibited by ATM kinase, resulting in p53 activation. However, how Apak is regulated in response to oncogenic stress remains unknown. Here we show that upon oncogene activation, Apak is inhibited in the tumor suppressor ARF-dependent but ATM-independent manner. Oncogene-induced ARF protein directly interacts with Apak and competes with p53 to bind to Apak, resulting in Apak dissociation from p53. Thus, Apak is differentially regulated in the ARF and ATM-dependent manner in response to oncogenic stress and DNA damage, respectively.

Structured summary

MINT-7989670: p53 (uniprotkb:P04637) binds (MI:0407) to APAK (uniprotkb:Q8TAQ5) by pull down (MI:0096)MINT-7989812: HDM2 (uniprotkb:Q00987) physically interacts (MI:0915) with ARF (uniprotkb:Q8N726-1) by anti bait coimmunoprecipitation (MI:0006)MINT-7989603, MINT-7989626: APAK (uniprotkb:Q8TAQ5) physically interacts (MI:0915) with ARF (uniprotkb:Q8N726-1) by anti bait coimmunoprecipitation (MI:0006)MINT-7989653: ARF (uniprotkb:Q8N726-1) binds (MI:0407) to APAK (uniprotkb:Q8TAQ5) by pull down (MI:0096)MINT-7989686, MINT-7989705, MINT-7989747:APAK (uniprotkb:Q8TAQ5) physically interacts (MI:0915) with ARF (uniprotkb:Q8N726-1) by anti tag coimmunoprecipitation (MI:0007)MINT-7989724: APAK (uniprotkb:Q8TAQ5) physically interacts (MI:0914) with ARF (uniprotkb:Q8N726-1) and p53 (uniprotkb:P04637) by anti tag coimmunoprecipitation (MI:0007)MINT-7989635: ARF (uniprotkb:Q8N726-1) and APAK (uniprotkb:Q8TAQ5) colocalize (MI:0403) by fluorescence microscopy (MI:0416)MINT-7989584, MINT-7989773: APAK (uniprotkb:Q8TAQ5) physically interacts (MI:0915) with p53 (uniprotkb:P04637) by anti tag coimmunoprecipitation (MI:0007)     

NMDA receptors interact with flotillin-1 and -2, lipid raft-associated proteins

N-methyl-d-aspartate receptors (NMDARs) mediate excitatory synaptic transmission in the brain. Here we demonstrate interactions between the NR2A and NR2B subunits of NMDARs with flotillin-1 (flot-1), a lipid raft-associated protein. When mapped, analogous regions in the far distal C-termini of NR2A and NR2B mediate binding to flot-1, and the prohibitin homology domain of flot-1 contains binding sites for NR2A and NR2B. Although NR2B can also directly bind to flot-2 via a separate region of its distal C-terminus, NMDARs were significantly more colocalized with flot-1 than flot-2 in cultured hippocampal neurons. Overall, this study defines a novel interaction between NMDARs and flotillins.

Structured summary

MINT-7013094: NR2A (uniprotkb:Q00959), NR2B (uniprotkb:Q00960) and Flot2 (uniprotkb:Q9Z2S9) colocalize (MI:0403) by fluorescence microscopy (MI:0416)MINT-7013147: Flot1 (uniprotkb:Q9Z1E1) physically interacts (MI:0218) with NR2A (uniprotkb:Q00959) by anti bait coimmunoprecipitation (MI:0006)MINT-7013189: Flot1 (uniprotkb:Q9Z1E1) physically interacts (MI:0218) with Flot2 (uniprotkb:Q9Z2S9) by anti bait coimmunoprecipitation (MI:0006)MINT-7013033: NR2A (uniprotkb:Q00959) physically interacts (MI:0218) with Flot1 (uniprotkb:Q9Z1E1) by two hybrid (MI:0018)MINT-7013178: NR1 (uniprotkb:P35439) physically interacts (MI:0218) with Flot2 (uniprotkb:Q9Z2S9) by anti bait coimmunoprecipitation (MI:0006)MINT-7013197, MINT-7013210: NR2B (uniprotkb:Q00960) and NR2A (uniprotkb:Q00959) physically interact (MI:0218) with Flot2 (uniprotkb:Q9Z2S9) by anti bait coimmunoprecipitation (MI:0006)MINT-7013002: NR2B (uniprotkb:Q00960) physically interacts (MI:0218) with Flot1 (uniprotkb:O08917) by two hybrid (MI:0018)MINT-7013117: Flot1 (uniprotkb:Q9Z1E1), NR2B (uniprotkb:Q00960) and NR2A (uniprotkb:Q00959) colocalize (MI:0403) by fluorescence microscopy (MI:0416)MINT-7013171: NR1 (uniprotkb:P35439) physically interacts (MI:0218) with Flot1 (uniprotkb:Q9Z1E1) by anti bait coimmunoprecipitation (MI:0006)MINT-7013017: NR2A (uniprotkb:Q00959) physically interacts (MI:0218) with Flot1 (uniprotkb:O08917) by two hybrid (MI:0018)MINT-7013054: NR2B (uniprotkb:Q00960) physically interacts (MI:0218) with Flot1 (uniprotkb:Q9Z1E1) by two hybrid (MI:0018)MINT-7013129: Flot1 (uniprotkb:Q9Z1E1) physically interacts (MI:0218) with NR2B (uniprotkb:Q00960) by anti bait coimmunoprecipitation (MI:0006)MINT-7013155: NR1 (uniprotkb:P35439) physically interacts (MI:0218) with NR2B (uniprotkb:Q00960) by anti bait coimmunoprecipitation (MI:0006)MINT-7013074: NR2B (uniprotkb:Q00960) physically interacts (MI:0218) with Flot2 (uniprotkb:Q9Z2S9) by two hybrid (MI:0018)MINT-7013162: NR1 (uniprotkb:P35439) physically interacts (MI:0218) with NR2A (uniprotkb:Q00959) by anti bait coimmunoprecipitation (MI:0006)     

Transcriptional activation of hypoxia-inducible factor-1α by HDAC4 and HDAC5 involves differential recruitment of p300 and FIH-1

The interplay between hypoxia-inducible factor-1α (HIF-1α) and histone deacetylase (HDACs) have been well studied; however, the mechanism of cross-talk is unclear. Here, we investigated the roles of HDAC4 and HDAC5 in the regulation of HIF-1α function and its associated mechanisms. HDAC4 and HDAC5 enhanced transactivation by HIF-1α without stabilizing HIF-1α. HDAC4 and HDAC5 physically associated with HIF-1α through the inhibitory domain (ID) that is the binding site for factor inhibiting HIF-1 (FIH-1). In the presence of these HDACs, binding of HIF-1α to FIH-1 decreased, whereas binding to p300 increased. These results indicate that HDAC4 and HDAC5 increase the transactivation function of HIF-1α by promoting dissociation of HIF-1α from FIH-1 and association with p300.

Structured summary:

MINT-6802187:HIF1 alpha (uniprotkb:Q16665) physically interacts (MI:0218) with FIH1 (uniprotkb:Q9NWT6) by anti bait coimmunoprecipitation (MI:0006)MINT-6802058:HIF1 alpha (uniprotkb:Q16665) physically interacts (MI:0218) with HDAC4 (uniprotkb:P56524) by pull down (MI:0096)MINT-6802021:HIF1 alpha (uniprotkb:Q61221) physically interacts (MI:0218) with HDAC4 (uniprotkb:P56524) by anti bait coimmunoprecipitation (MI:0006)MINT-6802036:HIF1 alpha (uniprotkb:Q61221) physically interacts (MI:0218) with HDAC5 (uniprotkb:Q9UQL6) by anti bait coimmunoprecipitation (MI:0006)MINT-6802102:HIF1 alpha (uniprotkb:Q16665) physically interacts (MI:0218) with HDAC5 (uniprotkb:Q9UQL6) by pull down (MI:0096)MINT-6802121, MINT-6802156:P300 (uniprotkb:Q09472) physically interacts (MI:0218) with HIF1 alpha (uniprotkb:Q16665) by anti bait coimmunoprecipitation (MI:0006)     

c-Abl tyrosine kinase interacts with MAVS and regulates innate immune response

The tyrosine kinase, c-Abl, plays important roles in many aspects of cellular function. Previous reports showed that c-Abl is involved in NF-κB signaling. However, the functions of c-Abl in innate immunity are still unknown. Here we demonstrate that the mitochondrial antiviral signaling (MAVS) protein can be physically associated with c-Abl in vivo and in vitro. MAVS interacted with c-Abl through its Card and TM domain. A phosphotyrosine-specific antibody indicated that MAVS was phosphorylated by c-Abl. Functional impairment of c-Abl attenuated MAVS or VSV induced type-I IFN production. Importantly, c-Abl knockdown in MCF7 cells displayed impaired MAVS-mediated NF-κB and IRF3 activation. Taken together, our results suggest that c-Abl modulates innate immune response through MAVS.

Structured summary

MINT-7297498, MINT-7297511, MINT-7297557, MINT-7297574: MAVS (uniprotkb:Q7Z434) physically interacts (MI:0915) with c-Abl (uniprotkb:P00519) by anti tag coimmunoprecipitation (MI:0007)MINT-7297542: c-Abl (uniprotkb:P00519) physically interacts (MI:0915) with MAVS (uniprotkb:Q7Z434) by anti bait coimmunoprecipitation (MI:0006)MINT-7297526: c-Abl (uniprotkb:P00519) physically interacts (MI:0915) with MAVS (uniprotkb:Q7Z434) by far western blotting (MI:0047)     

Interaction of Beclin 1 with survivin regulates sensitivity of human glioma cells to TRAIL-induced apoptosis

We reported a novel interaction between Beclin 1, a key regulator of autophagy, and survivin, a member of the inhibitor of apoptosis protein family. We found that knock-down of Beclin 1 down-regulated survivin protein, and the turnover rate of survivin was increased when Beclin 1 expression was silenced. Knock-down of Beclin 1 sensitized glioma cells to TRAIL-induced apoptosis, and introduction of survivin antagonized the sensitizing effect, suggesting that down-regulation of survivin mediates the enhanced sensitivity to TRAIL-induced apoptosis. These results demonstrate a novel interaction between Beclin 1 and survivin, and may provide a potential mechanism underlying the cross-talk between autophagy and apoptosis.

Structured summary

MINT-7969366: Beclin-1 (uniprotkb:Q14457) physically interacts (MI:0915) with survivin (uniprotkb:O15392) by anti tag coimmunoprecipitation (MI:0007)MINT-7968986, MINT-7969161: survivin (uniprotkb:O15392) physically interacts (MI:0915) with Beclin-1 (uniprotkb:Q14457) by anti bait coimmunoprecipitation (MI:0006)     

BimL directly neutralizes Bcl-xL to promote Bax activation during UV-induced apoptosis

Bcl-2-interacting mediator of cell death (Bim) has been considered to initiate intrinsic apoptotic pathway through Bax activation. Previous studies indicated that BimL was involved in UV-induced apoptosis, but it remains unclear whether Bim activates Bax by directly engaging it or by releasing it from pro-survival relatives such as Bcl-xL. In this study, we attempt to determine the interactions between BimL and Bax/Bcl-xL during Ultraviolet (UV)-induced apoptosis. BimL activation appeared to be an important event in our experiments, as demonstrated by the significant inhibition of cell death, caspase-3 activity, and Bax translocation in cells with knockdown of endogenous BimL by RNAi approach. Both fluorescence resonance energy transfer (FRET) and Co-immunoprecipitation (CO-IP) assays indicated that Bcl-xL directly bound to Bax to inhibit its activation, while BimL directly neutralized Bcl-xL, followed by Bax release and activation upon UV irradiation. Not detected in our experiment was the interaction between BimL and Bax either using FRET approach in living cells or endogenous CO-IP assay. Thus, our findings provide strong evidence in living cells for the first time that BimL initiates apoptosis by abrogating Bcl-xL and promoting Bax activation under UV irradiation.

Structured summary

MINT-7034091: BIML (uniprotkb:O43521) physically interacts (MI:0218) with Bcl2-Xl (uniprotkb:Q92934) by anti bait coimmunoprecipitation (MI:0006)MINT-7034079: Bcl2-Xl (uniprotkb:Q92934) physically interacts (MI:0218) with BAX (uniprotkb:Q07812) and BIML (uniprotkb:O43521) by anti bait coimmunoprecipitation (MI:0006)MINT-7034069: BAX (uniprotkb:Q07812) physically interacts (MI:0218) with BIML (uniprotkb:O43521) by anti bait coimmunoprecipitation (MI:0006)MINT-7034114: BIML (uniprotkb:O43521) and BAX (uniprotkb:Q07812) physically interact (MI:0218) by fluorescent resonance energy transfer (MI:0055)     

A newly identified Pirh2 substrate SCYL1-BP1 can bind to MDM2 and accelerate MDM2 self-ubiquitination

The SCY1-like 1 binding protein 1 (SCYL1-BP1) protein was identified as an interacting partner of E3 ligase p53-induced RING H2 protein (Pirh2) and mouse double minute gene number 2 (MDM2) by yeast two-hybrid screening. Further investigation suggested there are two interactions involved in different mechanisms. SCYL1-BP1 can be ubiquitinated and degraded by Pirh2 but not by MDM2, which suggests that SCYL1-BP1 can be regulated by Pirh2. On the other hand, while SCYL1-BP1 binds to ubiquitin E3 ligase MDM2, it promotes MDM2 self-ubiquitination and results in a reduction of MDM2 protein level.

Structured summary

MINT-7904819, MINT-7904837, MINT-7904806, MINT-7904715: MDM2 (uniprotkb:Q00987) physically interacts (MI:0915) with SCYL1-BP1 (uniprotkb:Q5T7V8) by anti tag coimmunoprecipitation (MI:0007)MINT-7904857, MINT-7904899: SCYL1-BP1 (uniprotkb:Q5T7V8) physically interacts (MI:0915) with MDM2 (uniprotkb:Q00987) by anti bait coimmunoprecipitation (MI:0006)     

Regulation of HOXA2 gene expression by the ATP-dependent chromatin remodeling enzyme CHD8

Chromodomain, helicase, DNA-binding protein 8 (CHD8) is an ATP-dependent chromatin remodeling enzyme that has been demonstrated to exist within a large protein complex which includes WDR5, Ash2L, and RbBP5, members of the Mixed Lineage Leukemia (MLL) histone modifying complexes. Here we show that CHD8 relocalizes to the promoter of the MLL regulated gene HOXA2 upon gene activation. Depletion of CHD8 enhances HOXA2 expression under activating conditions. Furthermore, depletion of CHD8 results in a loss of the WDR5/Ash2L/RbBP5 subcomplex, and consequently H3K4 trimethylation, at the HOXA2 promoter. These studies suggest that CHD8 alters HOXA2 gene expression and regulates the recruitment of chromatin modifying enzymes.

Structured summary

MINT-7542810: CHD8 (uniprotkb:Q9HCK8) physically interacts (MI:0915) with RbBP5 (uniprotkb:Q15291) by anti tag coimmunoprecipitation (MI:0007)MINT-7542794: CHD8 (uniprotkb:Q9HCK8) physically interacts (MI:0915) with WDR5 (uniprotkb:P61964) by anti tag coimmunoprecipitation (MI:0007)MINT-7542820: CHD8 (uniprotkb:Q9HCK8) physically interacts (MI:0915) with ASH2L (uniprotkb:Q9UBL3) by anti tag coimmunoprecipitation (MI:0007)MINT-7542769: CHD8 (uniprotkb:Q9HCK8) physically interacts (MI:0914) with RbBP5 (uniprotkb:Q15291), ASH2L (uniprotkb:Q9UBL3) and WDR5 (uniprotkb:P61964) by anti tag coimmunoprecipitation (MI:0007)     

Serine 62 is a phosphorylation site in folliculin, the Birt-Hogg-Dubé gene product

Recently, it was reported that the product of Birt-Hogg-Dubé syndrome gene (folliculin, FLCN) is directly phosphorylated by 5′-AMP-activated protein kinase (AMPK). In this study, we identified serine 62 (Ser62) as a phosphorylation site in FLCN and generated an anti-phospho-Ser62-FLCN antibody. Our analysis suggests that Ser62 phosphorylation is indirectly up-regulated by AMPK and that another residue is directly phosphorylated by AMPK. By binding with FLCN-interacting proteins (FNIP1 and FNIP2/FNIPL), Ser62 phosphorylation is increased. A phospho-mimic mutation at Ser62 enhanced the formation of the FLCN-AMPK complex. These results suggest that function(s) of FLCN-AMPK-FNIP complex is regulated by Ser62 phosphorylation.

Structured summary

MINT-7298145, MINT-7298166: Flcn (uniprotkb:Q76JQ2) physically interacts (MI:0915) with AMPK alpha 1 (uniprotkb:P54645) by anti tag coimmunoprecipitation (MI:0007)MINT-7298267: AMPK alpha 1 (uniprotkb:Q13131) phosphorylates (MI:0217) tsc2 (uniprotkb:P49816) by protein kinase assay (MI:0424)MINT-7298182: FNIP1 (uniprotkb:Q8TF40) physically interacts (MI:0915) with Flcn (uniprotkb:Q76JQ2) by anti tag coimmunoprecipitation (MI:0007)MINT-7298132: AMPK alpha 1 (uniprotkb:Q13131) phosphorylates (MI:0217) Flcn (uniprotkb:Q76JQ2) by protein kinase assay (MI:0424)MINT-7298229: FNIPL (uniprotkb:Q9P278) physically interacts (MI:0915) with Flcn (uniprotkb:Q76JQ2) by anti tag coimmunoprecipitation (MI:0007)     

HECT ubiquitin ligase Smurf1 targets the tumor suppressor ING2 for ubiquitination and degradation

Inhibitor of growth 2 (ING2) gene encodes a candidate tumor suppressor and is frequently reduced in many tumors. However, the mechanisms underlying the regulation of ING2, in particular its protein stability, are still unclear. Here we show that the homologous to E6AP carboxyl terminus (HECT)-type ubiquitin ligase Smad ubiquitination regulatory factor 1 (Smurf1) interacts with and targets ING2 for poly-ubiquitination and proteasomal degradation. Intriguingly, the ING2 binding domain in Smurf1 was mapped to the catalytic HECT domain. Furthermore, the C-terminal PHD domain of ING2 was required for Smurf1-mediated degradation. This study provided the first evidence that the stability of ING2 could be regulated by ubiquitin-mediated degradation.

Structured summary

MINT-7894271: ING2 (uniprotkb:Q9H160) binds (MI:0407) to Smurf1 (uniprotkb:Q9HCE7) by pull-down (MI:0096)MINT-7894319, MINT-7894339: ING2 (uniprotkb:Q9H160) physically interacts (MI:0915) with Smurf1 (uniprotkb:Q9HCE7) by anti tag co-immunoprecipitation (MI:0007)MINT-7894301: Smurf1 (uniprotkb:Q9HCE7) physically interacts (MI:0915) with ING2 (uniprotkb:Q9H160) by anti bait co-immunoprecipitation (MI:0006)MINT-7894358: ING1b (uniprotkb:Q9UK53-2) physically interacts (MI:0915) with Smurf1 (uniprotkb:Q9HCE7) by anti tag co-immunoprecipitation (MI:0007)MINT-7894249: ING2 (uniprotkb:Q9H160) physically interacts (MI:0915) with ubiquitin (uniprotkb:P62988) by anti tag co-immunoprecipitation (MI:0007)     

Interaction of human immunodeficiency virus gp120 with the voltage-gated potassium channel BEC1

Retrovirus replication critically depends on a dynamic interplay between retroviral and host proteins. We report on the binding of the surface subunit (glycoprotein 120 (gp120)) of the human immunodeficiency virus type 1 (HIV-1) envelope protein (Env) to the cytoplasmic C-terminus of the voltage-gated potassium channel BEC1 (brain-specific ether-a-go-go-like channel 1), an interaction that can result in the repression of BEC’s activity and the inhibition of HIV-1 particle-release. BEC1 protein was found to be expressed in T cells and macrophages, the major target cells of HIV-1. Thus, gp120/BEC1 interaction may be involved in HIV-1 life cycle and/or pathogenesis.

Structured summary

MINT-7968695: BEC1 (uniprotkb:Q9ULD8) physically interacts (MI:0915) with gp160 (uniprotkb:P04578) by anti bait coimmunoprecipitation (MI:0006)MINT-7968714: BEC1 (uniprotkb:Q9ULD8) physically interacts (MI:0915) with gp160 (uniprotkb:P04578) by anti tag coimmunoprecipitation (MI:0007)MINT-7968675: BEC1 (uniprotkb:Q9ULD8) physically interacts (MI:0915) with gp160 (uniprotkb:P04578) by pull down (MI:0096)     

The interaction between EAP30 and ELL is modulated by MCM2

ELL-associated protein 30 (EAP30) was initially characterized as a component of the Holo-ELL complex, which contains the elongation factor ELL. Both ELL and Holo-ELL stimulate RNA pol II elongation in vitro. However, ELL and not Holo-ELL inhibits RNA pol II initiation. It is not clear how these two discrete functions of ELL are regulated. Here we report that mini-chromosome maintenance 2 (MCM2) binds to EAP30 and show that MCM2 competes with ELL for binding to EAP30 thus potentially modulating the stability of Holo-ELL.

Structured summary

MINT-7277033: EAP30 (uniprotkb:Q96H20) physically interacts (MI:0915) with RPB1 (uniprotkb:P24928) by anti tag coimmunoprecipitation (MI:0007)MINT-7277085: EAP30 (uniprotkb:Q96H20) binds (MI:0407) to ELL (uniprotkb:P55199) by pull down (MI:0096)MINT-7277072: EAP30 (uniprotkb:Q96H20) physically interacts (MI:0915) with ELL (uniprotkb:P55199) by anti tag coimmunoprecipitation (MI:0007)MINT-7277100: EAP30 (uniprotkb:Q96H20) physically interacts (MI:0915) with ELL (uniprotkb:P55199) by competition binding (MI:0405)MINT-7277153: MCM2 (uniprotkb:P49736) binds (MI:0407) to ELL (uniprotkb:P55199) by pull down (MI:0096)MINT-7276989: EAP30 (uniprotkb:Q96H20) physically interacts (MI:0915) with MCM2 (uniprotkb:P49736) by pull down (MI:0096)MINT-7277005: EAP30 (uniprotkb:Q96H20) physically interacts (MI:0915) with RPB1 (uniprotkb:P24928) by pull down (MI:0096)MINT-7276960, MINT-7277168: MCM2 (uniprotkb:P49736) physically interacts (MI:0915) with EAP30 (uniprotkb:Q96H20) by two hybrid (MI:0018)MINT-7276971, MINT-7277121, MINT-7277137: MCM2 (uniprotkb:P49736) binds (MI:0407) to EAP30 (uniprotkb:Q96H20) by pull down (MI:0096)MINT-7277018, MINT-7277061: EAP30 (uniprotkb:Q96H20) physically interacts (MI:0915) with MCM2 (uniprotkb:P49736) by anti tag coimmunoprecipitation (MI:0007)     

Myeloid translocation gene 16b is a dual A-kinase anchoring protein that interacts selectively with plexins in a phospho-regulated manner

The myeloid translocation gene (MTG) homologue Nervy associates with PlexinA on the plasma membrane, where it functions as an A-kinase anchoring protein (AKAP) to modulate plexin-mediated semaphorin signaling in Drosophila. Mammalian MTG16b is an AKAP found in immune cells where plexin-mediated semaphorin signaling regulates immune responses. This study provides the first evidence that MTG16b is a dual AKAP capable of binding plexins. These interactions are selective (PlexinA1 and A3 bind MTG, while PlexinB1 does not) and can be regulated by PKA-phosphorylation. Collectively, these data suggest a possible mechanism for the targeting and integration of adenosine 3′,5′-cyclic monophosphate (cAMP) and semaphorin signaling in immune cells.

Structured summary

MINT-7556975: PlexinA3 (uniprotkb:P51805) physically interacts (MI:0915) with MTG 16b (uniprotkb:O75081) by anti tag coimmunoprecipitation (MI:0007)MINT-7557008: RI alpha (uniprotkb:Q9DBC7) physically interacts (MI:0915) with MTG 16b (uniprotkb:O75081) by anti bait coimmunoprecipitation (MI:0006)MINT-7556989: MTG 16b (uniprotkb:O75081) physically interacts (MI:0915) with PlexinA3 (uniprotkb:P51805) by pull down (MI:0096)     

S100 proteins regulate the interaction of Hsp90 with Cyclophilin 40 and FKBP52 through their tetratricopeptide repeats

S100 proteins are a subfamily of the EF-hand type calcium sensing proteins, the exact biological functions of which have not been clarified yet. In this work, we have identified Cyclophilin 40 (CyP40) and FKBP52 (called immunophilins) as novel targets of S100 proteins. These immunophilins contain a tetratricopeptide repeat (TPR) domain for Hsp90 binding. Using glutathione-S transferase pull-down assays and immunoprecipitation, we have demonstrated that S100A1 and S100A2 specifically interact with the TPR domains of FKBP52 and CyP40 in a Ca²⁺-dependent manner, and lead to inhibition of the CyP40-Hsp90 and FKBP52-Hsp90 interactions. These findings have suggested that the Ca²⁺/S100 proteins are TPR-targeting regulators of the immunophilins-Hsp90 complex formations.

Structured summary

MINT-7710442: FKBP52 (uniprotkb:Q02790) physically interacts (MI:0915) with S100A6 (uniprotkb:P06703) by competition binding (MI:0405)MINT-7710192: Cyp40 (uniprotkb:P26882) binds (MI:0407) to S100A1 (uniprotkb:P35467) by pull down (MI:0096)MINT-7710412: Cyp40 (uniprotkb:P26882) physically interacts (MI:0915) with S100A2 (uniprotkb:P29034) by competition binding (MI:0405)MINT-7710374: FKBP52 (uniprotkb:Q02790) binds (MI:0407) to S100A2 (uniprotkb:P29034) by pull down (MI:0096)MINT-7710452: Cyp40 (uniprotkb:P26882) physically interacts (MI:0914) with S100A2 (uniprotkb:P29034) and Hsp90 (uniprotkb:P07900) by anti tag coimmunoprecipitation (MI:0007)MINT-7710387: FKBP52 (uniprotkb:Q02790) binds (MI:0407) to S100A6 (uniprotkb:P06703) by pull down (MI:0096)MINT-7710279: FKBP52 (uniprotkb:Q02790) physically interacts (MI:0915) with S100A1 (uniprotkb:P35467) by competition binding (MI:0405)MINT-7710224: FKBP52 (uniprotkb:Q02790) binds (MI:0407) to Hsp90 (uniprotkb:P07900) by pull down (MI:0096)MINT-7710464: Cyp40 (uniprotkb:P26882) physically interacts (MI:0914) with S100A6 (uniprotkb:P06703) and Hsp90 (uniprotkb:P07900) by anti tag coimmunoprecipitation (MI:0007)MINT-7710249: Cyp40 (uniprotkb:P26882) binds (MI:0407) to Hsp90 (uniprotkb:P07900) by pull down (MI:0096)MINT-7710422: Cyp40 (uniprotkb:P26882) physically interacts (MI:0915) with S100A6 (uniprotkb:P06703) by competition binding (MI:0405)MINT-7710348: Cyp40 (uniprotkb:P26882) binds (MI:0407) to S100A2 (uniprotkb:P29034) by pull down (MI:0096)MINT-7710208: FKBP52 (uniprotkb:Q02790) binds (MI:0407) to S100A1 (uniprotkb:P35467) by pull down (MI:0096)MINT-7710265: Cyp40 (uniprotkb:P26882) physically interacts (MI:0915) with S100A1 (uniprotkb:P35467) by competition binding (MI:0405)MINT-7710361: Cyp40 (uniprotkb:P26882) binds (MI:0407) to S100A6 (uniprotkb:P06703) by pull down (MI:0096)MINT-7710476: FKBP52 (uniprotkb:Q02790) physically interacts (MI:0914) with S100A2 (uniprotkb:P29034) and Hsp90 (uniprotkb:P07900) by anti tag coimmunoprecipitation (MI:0007)MINT-7710316: FKBP52 (uniprotkb:Q02790) physically interacts (MI:0914) with S100A1 (uniprotkb:P35467) and Hsp90 (uniprotkb:P07900) by anti tag coimmunoprecipitation (MI:0007)MINT-7710432: FKBP52 (uniprotkb:Q02790) physically interacts (MI:0915) with S100A2 (uniprotkb:P29034) by competition binding (MI:0405)MINT-7710488: FKBP52 (uniprotkb:Q02790) physically interacts (MI:0914) with S100A6 (uniprotkb:P06703) and Hsp90 (uniprotkb:P07900) by anti tag coimmunoprecipitation (MI:0007)MINT-7710329: S100A6 (uniprotkb:P14069) physically interacts (MI:0914) with FKBP52 (uniprotkb:P30416) and Cyp40 (uniprotkb:Q08752) by anti bait coimmunoprecipitation (MI:0006)MINT-7710295: Cyp40 (uniprotkb:P26882) physically interacts (MI:0914) with Hsp90 (uniprotkb:P07900) and S100A1 (uniprotkb:P35467) by anti tag coimmunoprecipitation (MI:0007)     

Beta-2 adrenergic receptor mediated ERK activation is regulated by interaction with MAGI-3

The beta-2 adrenergic receptor (β2AR) has a carboxyl terminus motif that can interact with PSD-95/discs-large/ZO1 homology (PDZ) domain-containing proteins. In this paper, we identified membrane-associated guanylate kinase inverted-3 (MAGI-3) as a novel binding partner of β2AR. The carboxyl terminus of β2AR binds with high affinity to the fifth PDZ domain of MAGI-3, with the last four amino acids (D-S-L-L) of the receptor being the key determinants of the interaction. In cells, the association of full-length β2AR with MAGI-3 occurs constitutively and is enhanced by agonist stimulation of the receptor. Our data also demonstrated that β2AR-stimulated extracellular signal-regulated kinase-1/2 (ERK1/2) activation was substantially retarded by MAGI-3 expression. These data suggest that MAGI-3 regulates β2AR-mediated ERK activation through the physical interaction between β2AR and MAGI-3.

Structured summary

MINT-7716556: beta2AR (uniprotkb:P07550) physically interacts (MI:0915) with MAGI-3 (uniprotkb:Q5TCQ9) by anti tag coimmunoprecipitation (MI:0007)MINT-7716593: beta2AR (uniprotkb:P18762) physically interacts (MI:0915) with MAGI-3 (uniprotkb:Q9EQJ9) by anti bait coimmunoprecipitation (MI:0006)MINT-7716630: MAGI-3 (uniprotkb:Q5TCQ9) and beta2AR (uniprotkb:P07550) colocalize (MI:0403) by fluorescence microscopy (MI:0416)MINT-7716382, MINT-7716335: MAGI-3 (uniprotkb:Q5TCQ9) physically interacts (MI:0915) with beta2AR (uniprotkb:P07550) by pull down (MI:0096)MINT-7716320, MINT-7716422, MINT-7716502, MINT-7716450, MINT-7716470: beta2AR (uniprotkb:P07550) binds (MI:0407) to MAGI-3 (uniprotkb:Q5TCQ9) by pull down (MI:0096)