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1.
Evolution of the Integrin α and β Protein Families 总被引:4,自引:0,他引:4
Hughes AL 《Journal of molecular evolution》2001,52(1):63-72
A phylogenetic analysis of vertebrate and invertebrate α integrins supported the hypothesis that two major families of vertebrate
α integrins originated prior to the divergence of deuterostomes and protostomes. These two families include, respectively,
the αPS1 and αPS2 integrins of Drosophila melanogaster, and each family has duplicated repeatedly in vertebrates but not in Drosophila. In contrast, a third family (including αPS3) has duplicated in Drosophila but is absent from vertebrates. Vertebrate αPS1 and αPS2 family members are found on human chromosomes 2, 12, and 17. Linkage
of these family members may have been conserved since prior to the origin of vertebrates, and the two genes duplicated simultaneously.
A phylogenetic analysis of β integrins did not clearly resolve whether vertebrate β integrin genes duplicated prior to the
origin of vertebrates, although it suggested that at least the gene encoding vertebrate β4 may have done so. In general, the
phylogeny of neither α nor β integrins showed a close correspondence with patterns of α–β heterodimer formation or other functional
characteristics. One major exception to this trend involved αL, αM, αX, and αD, a monophyletic group of immune cell-expressed
α integrins, which share a number of common functional characteristics and have evolved in coordinated fashion with their
β integrin partners.
Received: 22 June 2000 / Accepted: 11 September 2000 相似文献
2.
3.
Nicholas H. Brown 《BioEssays : news and reviews in molecular, cellular and developmental biology》1993,15(6):383-390
The Drosophila position-specific (PS) integrins are members of the integrin family of cell surface receptors and are thought to be receptors for extracellular matrix components. Each PS integrin consists of an α subunit, αPS1 or αPS2, and a βPS subunit. Mutations in the βPS subunit and the αPS2 subunit have been characterised and reveal that the PS integrins have an essential role in the adhesion of different cell layers to each other. The PS integrins are especially required for the function of the cell-matrix-cell junctions, where the muscles attach to the epidermis and where one surface of the developing wing adheres to the other. These junctions are similar to vertebrate focal adhesions and hemidesmosomes, which also contain integrins. Integrin-mediated cell to cell adhesion via the extracellular matrix provides a way for tissues to adhere to each other without intermingling of their cells. 相似文献
4.
Muhamad Sahlan Taro Kanzaki Masafumi Yohda 《Extremophiles : life under extreme conditions》2009,13(3):437-445
The hyperthermophilic archaeon Thermococcus sp. strain KS-1 (T. KS-1) expresses two different chaperonin subunits, α and β, for the folding of its proteins. The composition of the subunits
in the hexadecameric double ring changes with temperature. The content of the β subunit significantly increases according
to the increase in temperature. The homo-oligomer of the β subunit, Cpnβ, is more thermostable than that of the α subunit,
Cpnα. Since Cpnα and Cpnβ also have different protein folding activities and interactions with prefoldin, the hetero-oligomer
is thought to exhibit different characteristics according to the content of subunits. The hetero-oligomer of the T. KS-1 chaperonin has not been studied, however, because the α and β subunits form hetero-oligomers of varying compositions
when they are expressed simultaneously. In this study, we characterized the T. KS-1 chaperonin hetero-oligomer, Cpnαβ, containing both α and β in the alternate order, which was constructed by the expression
of α and β subunits in a coordinated fashion and protease digestion. Cpnαβ protected citrate synthase from thermal aggregation,
promoted the folding of acid-denatured GFP in an ATP-dependent manner, and exhibited an ATP-dependent conformational change.
The yield of refolded GFP generated by Cpnαβ was almost equivalent to that generated by Cpnβ but lower than that generated
by Cpnα. In contrast, Cpnαβ exhibited almost the same level of thermal stability as Cpnα, which was lower than that of Cpnβ.
The affinity of Cpnαβ to prefoldin was found to be between those of Cpnα and Cpnβ, as expected. 相似文献
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6.
P. H. Benetti S. I. Kim M. Canonge T. Chardot J. C. Meunier 《Molecular & general genetics : MGG》1997,256(4):355-364
Casein kinase II from the yeast Yarrowia lipolytica is a heterotetramer of the form αα′β2. We report on the cloning and sequencing of a partial cDNA and of the complete genomic DNA coding for the catalytic α subunit
of the casein kinase II from this yeast species. The sequence of the gene coding for this enzyme has been analyzed. No intron
was found in the gene, which is present in a single copy. The deduced amino acid sequence of the gene shows high similarity
with those of α subunit described in other species, although, uniquely, Y. lipolytica CKIIα lacks cysteines. We find that the α subunit sequence of Y. lipolytica CKII is shown greater homology with the corresponding protein from S. pombe than with that from S. cerevisiae. We have analyzed CKIIα expression and CKIIα activity. We show that expression of this enzyme is regulated. The catalytic
subunit is translated from a single mRNA, and the enzyme is present at a very low level in Y. lipolytica, as in other yeasts.
Received: 20 December1997 / Accepted: 19 June 1997 相似文献
7.
Light-regulated localization of the beta-subunit of Gq-type G-protein in the crayfish photoreceptors 总被引:3,自引:0,他引:3
A. Terakita H. Takahama T. Hariyama T. Suzuki Y. Tsukahara 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1998,183(4):411-417
In crayfish photoreceptor cells, Gq-type G-protein plays a central role in the phototransduction pathway, and the translocation
of Gqα has been proposed as one of the molecular mechanisms to control photoreceptor sensitivity. We here investigated β subunit
of Gq and its localization profiles under various light conditions in the crayfish photoreceptor cells to understand the functional
characteristic of visual Gq in the phototransduction pathway. An immunoprecipitation experiment was performed using an anti-Gqα
antibody and a thiol-cleavable crosslinker. A 39 kDa protein was co-immunoprecipitated with Gqα, but not by irradiation, in
the presence of GTPγS. The partial amino acid sequence of the 39 kDa protein was similar to Gβe in Drosophila photoreceptors, indicating that the crayfish Gβ which combines with Gqα is a Gβe homologue. Immunohistochemical and immunoblot
analyses revealed that the amount of the Gβ decreased in the rhabdomeric membranes and increased in the cytoplasm in the light,
compared with that in the dark. The profile of the translocation was similar to that reported for Gqα. Since both α and βγ
subunits are necessary for G-proteins to be activated by rhodopsin in the rhabdom, the light-modulated translocation of a
Gβe homologue possibly controls the amount of Gq which can be activated by light-stimulated rhodopsin.
Accepted: 27 June 1998 相似文献
8.
9.
Andrew K. Jones Steven D. Buckingham Laurence A. Brown David B. Sattelle 《Invertebrate neuroscience : IN》2009,9(2):77-84
Nicotinic acetylcholine receptors (nAChRs) are the members of the cys-loop ligand-gated ion channel superfamily and are formed
by five subunits arranged around a central ion channel. Each subunit is encoded by a separate gene and is classified as either
α or non-α depending on the presence or absence, respectively, of two adjacent cysteine residues which are important for acetylcholine
binding. Here, we report for the first time a single nAChR gene encoding both α and non-α subunits. Specifically, alternative
splicing of the Anopheles gambiae nAChR subunit, previously called Agamα9 and renamed here Agamαβ9, generates two variants, one possessing the two cysteines
(denoted Agamαβ9α) and the other lacking the cysteine doublet (Agamαβ9β). Attempts to heterologously express functional nAChRs consisting of the Agamαβ9 splice variants in Xenopus laevis oocytes were unsuccessful. Our findings further characterise a potential target to control the malaria mosquito as well as
provide insights into the diversification of nAChRs. 相似文献
10.
Fangfang Zhong Jie Pan Xiaoxiao Liu Hongyan Wang Tianlei Ying Jihu Su Zhong-Xian Huang Xiangshi Tan 《Journal of biological inorganic chemistry》2011,16(8):1227-1239
Human soluble guanylate cyclase (sGC), a critical heme-containing enzyme in the NO-signaling pathway of eukaryotes, is an
αβ heterodimeric hemoprotein. Upon the binding of NO to the heme, sGC catalyzes the conversion of GTP to cyclic GMP, playing
a crucial role in many physiological processes. However, the specific contribution of the α and β subunits of sGC in the intact
heme binding remained intangible. The recombinant human sGC α1 subunit has been expressed in Escherichia coli and characterized for the first time. The heme binding and related NO/CO binding properties of both the α1 subunit and the
β1 subunit were investigated via heme reconstitution, UV–vis spectroscopy, EPR spectroscopy, stopped-flow kinetics, and homology
modeling. These results indicated that the α1 subunit of human sGC, lacking the conserved axial ligand, is likely to interact
with heme noncovalently. On the basis of the equilibrium and kinetics of CO binding to sGC, one possible CO binding model
was proposed. CO binds to human sGCβ195 by simple one-step binding, whereas CO binds to human sGCα259, possibly from both
axial positions through a more complex process. The kinetics of NO dissociation from human sGC indicated that the NO dissociation
from sGC was complex, with at least two release phases, and human sGCα259 has a smaller k
1 but a larger k
2. Additionally, the role of the cavity of the α1 subunit of human sGC was explored, and the results indicate that the cavity
likely accommodates heme. These results are beneficial for understanding the overall structure of the heme binding site of
the human sGC and the NO/CO signaling mechanism. 相似文献
11.
Subunit E of the vacuolar ATPase (V-ATPase) contains an N-terminal extended α helix (Rishikesan et al. J Bioenerg Biomembr
43:187–193, 2011) and a globular C-terminal part that is predicted to consist of a mixture of α-helices and β-sheets (Grüber et al. Biochem
Biophys Res Comm 298:383–391, 2002). Here we describe the production, purification and 2D structure of the C-terminal segment E133-222 of subunit E from Saccharamyces cerevisiae V-ATPase in solution based on the secondary structure calculation from NMR spectroscopy studies. E133-222 consists of four β-strands, formed by the amino acids from K136-V139, E170-V173, G186-V189, D195-E198 and two α-helices,
composed of the residues from R144-A164 and T202-I218. The sheets and helices are arranged as β1:α1:β2:β3:β4:α2, which are
connected by flexible loop regions. These new structural details of subunit E are discussed in the light of the structural
arrangements of this subunit inside the V1- and V1VO ATPase. 相似文献
12.
Rameshwaram NR Karanam NK Scharf C Völker U Nadimpalli SK 《Glycoconjugate journal》2009,26(2):161-172
A new unique lectin (galactose-specific) purified from the seeds of Dolichos lablab, designated as DLL-II is a heterodimer composed of closely related subunits α and β. These were separated by SDS-PAGE and
isolated by electroelution. By ESI-MS analysis their molecular masses were found to be 30.746 kDa (α) and 28.815 kDa (β) respectively.
Both subunits were glycosylated and displayed similar amino acid composition. Using advanced mass spectrometry in combination
with de novo sequencing and database searches for the peptides derived by enzymatic and chemical cleavage of these subunits, the primary
sequence was deduced. This revealed DLL-II to be made of two polypeptide chains of 281(α) and 263(β) amino acids respectively.
The β subunit differed from the α subunit by the absence of some amino acids at the carboxy terminal end. This structural
difference suggests that possibly, the β subunit is derived from the α subunit by posttranslational proteolytic modification
at the COOH-terminus. Comparison of the DLL-II sequence to other leguminous seed lectins indicates a high degree of structural
conservation.
Electronic Supplementary Material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
13.
The Fenna–Matthews–Olson protein is a water-soluble protein found only in green sulfur bacteria. Each subunit contains seven
bacteriochlorophyll (BChl) a molecules wrapped in a string bag of protein consisting of mostly β sheet. Most other chlorophyll-binding proteins are water-insoluble
proteins containing membrane-spanning α helices. We compared an FMO consensus sequence to well-characterized, membrane-bound
chlorophyll-binding proteins: L & M (reaction center proteins of proteobacteria), D1 & D2 (reaction center proteins of PS
II), CP43 & CP47 (core proteins of PS II), PsaA & PsaB (reaction center proteins of PS I), PscA (reaction center protein of
green sulfur bacteria), and PshA (reaction center protein of heliobacteria). We aligned the FMO sequence with the other sequences
using the PAM250 matrix modified for His binding-site identities and found a signature sequence (LxHHxxxGxFxxF) common to FMO and PscA. (The two His residues are BChl a. binding sites in FMO.) This signature sequence is part of a 220-residue C-terminal segment with an identity score of 13%.
PRSS (Probability of Random Shuffle) analysis showed that the 220-residue alignment is better than 96% of randomized alignments.
This evidence supports the hypothesis that FMO protein is related to PscA.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
14.
Jing Wu Min-Chen Wu Lian-Fen Zhang Jian-Yong Lei Lei Feng Jian Jin 《Journal of biosciences》2009,34(2):213-220
ADAM15 plays an important role in tumour development by interacting with integrins. In this study, we investigated the target
peptides of the ADAM15 disintegrin domain. First, we successfully produced the recombinant human ADAM15 disintegrin domain
(RADD) that could inhibit melanoma cell adhesion by using Escherichia coli. Second, four specific binding peptides (peptides A, B, C, and D) were selected using a phage display 12-mer peptide library.
The screening protocol involved 4 rounds of positive panning on RADD and 2 rounds of subtractive selection with streptavidin.
By using the BLAST software and a relevant protein database, integrin α
ν
β
3 was found to be homologous to peptide A. Synthetic peptide A had a highly inhibitory effect on RADD-integrin α
v
β
3 binding. The results demonstrate the potential application of short peptides for disrupting high-affinity ADAM-integrin interactions. 相似文献
15.
López-Hernández GY Biaggi-Labiosa NM Torres-Cintrón A Ortiz-Acevedo A Lasalde-Dominicci JA 《Cellular and molecular neurobiology》2009,29(1):41-53
Phosphorylation of the nicotinic acetylcholine receptor (nAChR) is believed to play a critical role in its nicotine-induced
desensitization and up-regulation. We examined the contribution of a consensus PKC site in the α4 M3/M4 intracellular loop
(α4S336) on the desensitization and up-regulation of α4β2 nAChRs expressed in oocytes. Position α4S336 was replaced with either
alanine to abolish potential phosphorylation at this site or with aspartic acid to mimic phosphorylation at this same site.
Mutations α4S336A and α4S336D displayed a threefold increase in the ACh-induced response and an increase in ACh EC50. Epibatidine binding revealed a three and sevenfold increase in surface expression for the α4S336A and α4S336D mutations,
respectively, relative to wild-type, therefore, both mutations enhanced expression of the α4β2 nAChR. Interestingly, the EC50’s and peak currents for nicotine activation remained unaffected in both mutants. Both mutations abolished the nicotine-induced
up-regulation that is normally observed in the wild-type. The present data suggest that adding or removing a negative charge
at this phosphorylation site cannot be explained by a simple straightforward on-and-off mechanism; rather a more complex mechanism(s)
may govern the functional expression of the α4β2 nAChR. Along the same line, our data support the idea that phosphorylation
at multiple consensus sites in the α4 subunit could play a remarkable role on the regulation of the functional expression
of the α4β2 nAChR. 相似文献
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18.
Lee S Jia B Pham BP Shao Y Kwak JM Cheong GW 《Extremophiles : life under extreme conditions》2012,16(1):87-93
Sarcosine oxidase (SOX) catalyzes the oxidation of the methyl group in sarcosine and transfer of the oxidized methyl group
into the one-carbon metabolic pool. Here, we separately cloned and expressed α and β subunit of SOX from Thermococcus kodakarensis KOD1 (TkSOX) in Escherichia coli and the recombinant proteins were purified to homogeneity. Gel filtration chromatography and transmission electron microscopy
analysis showed that the α subunit formed a dimeric structure and behaved as an NADH dehydrogenase; β subunit was a tetramer
that had sarcosine oxidase and l-proline dehydrogenase activity. The TkSOX complex assembled into the hetero-octameric (αβ)4 form and had NADH dehydrogenase activity. Gold-label analysis indicated that α and β subunits were oriented in the alternative
form. Based on these results, we suggested that TkSOX was a multifunctional enzyme and that each subunit and (αβ)4 complex may separately exist as a function enzyme in different conditions. 相似文献
19.
Summary
Drosophila imaginal disc cell lines were used to investigate various aspects of cellular adhesion in vitro. The distribution of PS integrins
and their involvement in cell-cell and cell-substrate adhesion were assessed with the monoclonal antibody aBG-1 against the
βPS subunit, and both forms of adhesion were found to be impeded by the presence of the antibody. Adhesion to a number of
extracellular matrix components was investigated, and the cells were found to adhere to human fibronectin. This adhesion was
inhibited by aBG-1. The adhesion molecule fasciclin III was also found in these cells. Given that the cells are competent
to perform cell-cell and cell-substrate adhesion, it was thought that apical basal polarity might be restored when other suitable
conditions were provided, i.e., an artificial basement layer with feeder cells to provide nutrients basally to the cells,
and some features of apical-basal morphology were seen in cells cultured under these conditions. 相似文献
20.
Kubiński K Domańska K Sajnaga E Mazur E Zieliński R Szyszka R 《Molecular and cellular biochemistry》2007,295(1-2):229-236
Protein kinase CK2 is a highly conserved Ser/Thr protein kinase that is ubiquitous among eucaryotic organisms and appears
to play an important role in many cellular functions. This enzyme in yeast has a tetrameric structure composed of two catalytic
(α and/or α′) subunits and two regulatory β and β′ subunits. Previously, we have reported isolation from yeast cells four
active forms of CK2, composed of αα′ββ′, α2ββ′, α′2ββ′ and a free α′-catalytic subunit. Now, we report that in Saccharomyces cerevisiae CK2 holoenzyme regulatory β subunit cannot substitute other β′ subunit and only both of them can form fully active enzymatic
unit. We have examined the subunit composition of tetrameric complexes of yeast CK2 by transformation of yeast strains containing
single deletion of the β or β′ regulatory subunits with vectors carrying lacking CKB1 or CKB2 genes. CK2 holoenzyme activity was restored only in cases when both of them were present in the cell. Additional, co-immunoprecypitation
experiments show that polyadenylation factor Fip1 interacts with catalytic α subunits of CK2 and interaction with beta subunits
in the holoenzyme decreases CK2 activity towards this protein substrate. These data may help to elucidate the role of yeast
protein kinase CK2β/β′ subunits in the regulation of holoenzyme assembly and phosphotransferase activity. 相似文献