Structurally similar but functionally diverse ZU5 domains in human erythrocyte ankyrin

The metazoan cell membrane is highly organized. Maintaining such organization and preserving membrane integrity under different conditions are accomplished through intracellular tethering to an extensive, flexible protein network. Spectrin, the principal component of this network, is attached to the membrane through the adaptor protein ankyrin, which directly bridges the interaction between β-spectrin and membrane proteins. Ankyrins have a modular structure that includes two tandem ZU5 domains. The first domain, ZU5A, is directly responsible for binding β-spectrin. Here, we present a structure of the tandem ZU5 repeats of human erythrocyte ankyrin. Structural and biophysical experiments show that the second ZU5 domain, ZU5B, does not participate in spectrin binding. ZU5B is structurally similar to the ZU5 domain found in the netrin receptor UNC5b supramodule, suggesting that it could interact with other domains in ankyrin. Comparison of several ZU5 domains demonstrates that the ZU5 domain represents a compact and versatile protein interaction module.     

新疆洋海古代大麻叶的大麻酚分析(英文)

为了检测新疆吐鲁番地区洋海古墓中2500年前大麻叶中两个大麻酚:四氢大麻酚(THC)与大麻二酚(CBD),采用高压液相分析技术(HPLC)测定26.716 g大麻叶中THC与CBD的含量分别为0.2928 mg与0.2830 mg,占叶重量的(0.110%)%与(0.106%)%。THC与CBD标准品从现代大麻叶中分离得到,通过波谱分析鉴定。     

CARD8 and NLRP1 undergo autoproteolytic processing through a ZU5-like domain

The "Function to Find Domain" (FIIND)-containing proteins CARD8 (Cardinal; Tucan) and NLRP1 (NALP1; NAC) are well known components of inflammasomes, multiprotein complexes responsible for activation of caspase-1, a regulator of inflammation and innate immunity. Although identified many years ago, the role of the FIIND is unknown. Here, we report that CARD8 and NLRP1 undergo autoproteolytic cleavage at a conserved SF/S motif within the FIIND. Using bioinformatics and computational modeling approaches, we detected striking structural similarity between the FIIND and the ZU5-UPA domain present in the autoproteolytic protein PIDD. This allowed us to generate a three-dimensional model and to gain insights in the molecular mechanism of the cleavage. Site-directed mutagenesis experiments revealed that the second serine of the SF/S motif is required for CARD8 and NLRP1 autoproteolysis. Furthermore, we discovered an important function for conserved glutamic acid and histidine residues, located in proximity of the cleavage site in regulating the autoprocessing efficiency. Altogether, these results identify a function for the FIIND and show that CARD8 and NLRP1 are ZU5-UPA domain-containing autoproteolytic proteins, thus suggesting a novel mechanism for regulating innate immune responses.     

浙江淳安千岛湖发现一例白化乌鸫

黄腹角雉(Tragopan caboti)为我国特有雉类,国家一级重点保护野生动物。2010至2021年通过视频监测技术、红外相机监测与人工观察,对浙江省乌岩岭国家级自然保护区内的黄腹角雉巢卵被天敌危害情况进行了调查。基于42个黄腹角雉人工巢监测数据(36巢视频远程监控,2巢红外相机监测,4巢人工观察),野生黄腹角雉巢被天敌破坏的比率为54.8%,其中91.3%被破坏巢中的卵为王锦蛇(Elaphe carinata)所捕食,表明王锦蛇是黄腹角雉巢卵最主要的天敌。捕食黄腹角雉卵的天敌还包括松鸦(Garrulus glandarius)与黄喉貂(Martes flavigula),可能的天敌有灰树鹊(Dendrocitta formosae)、黄腹鼬(Mustela kathiah)及短尾猴(Macaca arctoides)等。本研究基于视频资料揭示了野生黄腹角雉种群的天敌情况,结合文献资料,我们推测黄腹角雉较长的孵卵期与离巢时间可能是造成其巢卵损失率高的主要原因,本研究结果对这一濒危物种的保护与繁育工作具有重要意义。     

绒毡层小体,一种在花药绒毡层细胞中新发现的含油细胞器

绒毡层小体(tapetosome)是最近新发现的特异性出现在花药绒毡层细胞中的一种含油细胞器。现对这种细胞器的形态、结构、生化组成、与其他含油细胞器的不同以及它们在花粉外被形成过程中的作用和作用机制进行综述。     

Domain analyses of Usher syndrome causing Clarin-1 and GPR98 protein models

Usher syndrome is an autosomal recessive disorder that causes hearing loss, Retinitis Pigmentosa (RP) and vestibular dysfunction. It is clinically and genetically heterogeneous disorder which is clinically divided into three types i.e. type I, type II and type III. To date, there are about twelve loci and ten identified genes which are associated with Usher syndrome. A mutation in any of these genes e.g. CDH23, CLRN1, GPR98, MYO7A, PCDH15, USH1C, USH1G, USH2A and DFNB31 can result in Usher syndrome or non-syndromic deafness. These genes provide instructions for making proteins that play important roles in normal hearing, balance and vision. Studies have shown that protein structures of only seven genes have been determined experimentally and there are still three genes whose structures are unavailable. These genes are Clarin-1, GPR98 and Usherin. In the absence of an experimentally determined structure, homology modeling and threading often provide a useful 3D model of a protein. Therefore in the current study Clarin-1 and GPR98 proteins have been analyzed for signal peptide, domains and motifs. Clarin-1 protein was found to be without any signal peptide and consists of prokar lipoprotein domain. Clarin-1 is classified within claudin 2 super family and consists of twelve motifs. Whereas, GPR98 has a 29 amino acids long signal peptide and classified within GPCR family 2 having Concanavalin A-like lectin/glucanase superfamily. It was found to be consists of GPS and G protein receptor F2 domains and twenty nine motifs. Their 3D structures have been predicted using I-TASSER server. The model of Clarin-1 showed only α-helix but no beta sheets while model of GPR98 showed both α-helix and β sheets. The predicted structures were then evaluated and validated by MolProbity and Ramachandran plot. The evaluation of the predicted structures showed 78.9% residues of Clarin-1 and 78.9% residues of GPR98 within favored regions. The findings of present study has resulted in the three dimensional structure prediction and conserved domain analysis which will be quite beneficial in better understanding of molecular components, protein-protein interaction, clinical heterogeneity and pathophysiology of Usher syndrome.     

海南万泉河中发现外来有害种——马那瓜丽体鱼

2011年在海南琼海万泉河发现外来鱼种马那瓜丽体鱼(Parachromis managuensis)。该种为凶猛的肉食性鱼类,已在野外建立种群,可能会对本土鱼类产生不利影响。建议主管部门禁止人为放生。     

FH3, A Domain Found in Formins, Targets the Fission Yeast Formin Fus1 to the Projection Tip During Conjugation

Formins are involved in diverse aspects of morphogenesis, and share two regions of homology: FH1 and FH2. We describe a new formin homology region, FH3. FH3 is an amino-terminal domain that differs from the Rho binding site identified in Bni1p and p140mDia. The Schizosaccharomyces pombe formin Fus1 is required for conjugation, and is localized to the projection tip in cells of mating pairs. We replaced genomic fus1⁺ with green fluorescent protein (GFP)- tagged versions that lacked either the FH1, FH2, or FH3 domain. Deletion of any FH domain essentially abolished mating. FH3, but neither FH1 nor FH2, was required for Fus1 localization. An FH3 domain–GFP fusion protein localized to the projection tips of mating pairs. Thus, the FH3 domain alone can direct protein localization. The FH3 domains of both Fus1 and the S. pombe cytokinesis formin Cdc12 were able to localize GFP to the spindle pole body in half of the late G2 cells in a vegetatively growing population. Expression of both FH3-GFP fusions also affected cytokinesis. Overexpression of the spindle pole body component Sad1 altered the distribution of both Sad1 and the FH3-GFP domain. Together these data suggest that proteins at multiple sites can interact with FH3 domains.     

Extracellular Interaction between hCD98 and the PDZ Class II Domain of hCASK in Intestinal Epithelia

The extracellular domain of the glycoprotein-associated integrin hCD98 protrudes into the basolateral extracellular space of the intestine and contains a PDZ class II-binding domain (GLLLRFPYAA, amino acids 520-529). Protein-protein interaction studies in vitro as well as in human colonic sections and Caco2-BBE cells have revealed that hCD98 coimmunoprecipitated with the basolateral membrane-associated guanylate kinase hCASK and that this interaction occurred in a PDZ domain-dependent manner. These novel results, which provide the first evidence for a PDZ domain-dependent interaction between a membrane protein and an extracellular protein, open a new field of investigation related to extracellular signaling in cell biology.     

广西发现版纳鱼螈白化幼体一例

2007年5月,在广西北流市六麻镇捕到一例雄性版纳鱼螈(Ichthyophis bannanicus)白化幼体。该个体完全白化。体重9.1 g,全长195 mm,尾长3.85 mm,体宽10.36 mm,吻长3.09 mm,尾鳍高5.71 mm,吻端至第一环沟9.47 mm,吻端至第二环沟13.41 mm,鼻间距2.42 mm,眼间距5.17 mm。与正常个体对比发现:该白化幼体的尾长、体宽、尾鳍高大于正常范围,吻端至第二环沟小于正常范围,其余数据均在正常范围内。     

PKCε, Via its Regulatory Domain and Independently of its Catalytic Domain, Induces Neurite-like Processes in Neuroblastoma Cells

To investigate the role of protein kinase C (PKC) isoforms in regulation of neurite outgrowth, PKCalpha, betaII, delta, and epsilon fused to enhanced green fluorescent protein (EGFP) were transiently overexpressed in neuroblastoma cells. Overexpression of PKCepsilon-EGFP induced cell processes whereas the other isoforms did not. The effect of PKCepsilon-EGFP was not suppressed by the PKC inhibitor GF109203X. Instead, process formation was more pronounced when the regulatory domain was introduced. Overexpression of various fragments from PKCepsilon regulatory domain revealed that a region encompassing the pseudosubstrate, the two C1 domains, and parts of the V3 region were necessary and sufficient for induction of processes. By deleting the second C1 domain from this construct, a dominant-negative protein was generated which suppressed processes induced by full-length PKCepsilon and neurites induced during retinoic acid- and growth factor-induced differentiation. As with neurites in differentiated neuroblastoma cells, processes induced by the PKCepsilon- PSC1V3 protein contained alpha-tubulin, neurofilament-160, and F-actin, but the PKCepsilon-PSC1V3-induced processes lacked the synaptic markers synaptophysin and neuropeptide Y. These data suggest that PKCepsilon, through its regulatory domain, can induce immature neurite-like processes via a mechanism that appears to be of importance for neurite outgrowth during neuronal differentiation.     

The Nsp1p Carboxy-Terminal Domain Is Organized into Functionally Distinct Coiled-Coil Regions Required for Assembly of Nucleoporin Subcomplexes and Nucleocytoplasmic Transport

Nucleoporin Nsp1p, which has four predicted coiled-coil regions (coils 1 to 4) in the essential carboxy-terminal domain, is unique in that it is part of two distinct nuclear pore complex (NPC) subcomplexes, Nsp1p-Nup57p-Nup49p-Nic96p and Nsp1p-Nup82p-Nup159p. As shown by in vitro reconstitution, coiled-coil region 2 (residues 673 to 738) is sufficient to form heterotrimeric core complexes and can bind either Nup57p or Nup82p. Accordingly, interaction of Nup82p with Nsp1p coil 2 is competed by excess Nup57p. Strikingly, coil 3 and 4 mutants are still assembled into the core Nsp1p-Nup57p-Nup49p complex but no longer associate with Nic96p. Consistently, the Nsp1p-Nup57p-Nup49p core complex dissociates from the nuclear pores in nsp1 coil 3 and 4 mutant cells, and as a consequence, defects in nuclear protein import are observed. Finally, the nsp1-L640S temperature-sensitive mutation, which maps in coil 1, leads to a strong nuclear mRNA export defect. Thus, distinct coiled-coil regions within Nsp1p-C have separate functions that are related to the assembly of different NPC subcomplexes, nucleocytoplasmic transport, and incorporation into the nuclear pores.