Society of General Physiologists series最新文献

{"title":"Signaling through the focal adhesion kinase.","authors":"M D Schaller","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"52 ","pages":"241-55"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20153922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interactions between dystrophin and the sarcolemma membrane.","authors":"J S Chamberlain,&nbsp;K Corrado,&nbsp;J A Rafael,&nbsp;G A Cox,&nbsp;M Hauser,&nbsp;C Lumeng","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Dystrophin serves as a link between the subsarcolemmal cytoskeleton and the extracellular matrix. The NH2 terminus attaches to the cytoskeleton, while the COOH terminus attaches to the dystrophin associated protein (DAP) complex, which can be separated into the dystroglycan, sarcoglycan, and syntrophin subcomplexes. While the function of each DAP is not known, the dystroglycan complex binds laminin in the extracellular matrix, and binds the dystrophin COOH terminus in vitro. The syntrophins also bind the dystrophin COOH terminus in vitro, but no evidence has been reported for an interaction between dystrophin and the sarcoglycans. Human mutations have been found in dystrophin, the sarcoglycans and laminin, all of which lead to various types of muscular dystrophy. We have been studying the dystrophin domains necessary for formation of a functional complex by generating transgenic mdx (dystrophin minus) mice expressing internally truncated dystrophins. These mice provide in vivo models to study the localization of truncated dystrophin isoforms, the association of the truncated proteins with the DAP complex, and the functional capacity of the assembled DAP complexes. Expression of a dystrophin deleted for most of the NH2-terminal domain in mdx mice leads to only a mild dystrophy, indicating that dystrophin can attach to the cytoskeleton by multiple mechanisms. Truncation of the central rod domain leads to normal DAP complex formation and almost fully prevents development of dystrophy. Deletion analysis of the COOH-terminal regions indicates that a broad cysteine-rich domain is indispensable for dystrophin function. This region coincides with the in vitro identified beta-dystroglycan binding domain. Mice lacking this latter domain express very low levels of the sarcoglycans, indicating that the sarcoglycan complex binds dystrophin via dystroglycan. All deletion constructs tested lead to normal expression of the syntrophins, indicating that syntrophin associates with the DAP complex via multiple binding partners.</p>","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"52 ","pages":"19-29"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20154538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanical transduction by ion channels: how forces reach the channel.","authors":"F Sachs","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"52 ","pages":"209-18"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20153919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of cytoplasmic motors in post-Golgi vesicular traffic.","authors":"A Müsch,&nbsp;E Rodriguez-Boulan","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"52 ","pages":"55-67"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20154540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional studies of the membrane skeleton in Drosophila: identification of a positional cue that targets polarized membrane skeleton assembly.","authors":"R R Dubreuil,&nbsp;G R MacVicar,&nbsp;P B Maddux","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"52 ","pages":"91-106"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20154543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cytoskeletal regulation of membrane function. Proceedings of the 50th annual symposium of the Society of General Physiologists. Woods Hole, Massachusetts, 5-7 September 1996.","authors":"","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"52 ","pages":"1-280"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20216525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Involvement of the actin network in insulin signalling.","authors":"T Tsakiridis,&nbsp;Q Wang,&nbsp;C Taha,&nbsp;S Grinstein,&nbsp;G Downey,&nbsp;A Klip","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The purpose of the studies included in this chapter was to examine the role of the actin network in the propagation of insulin action leading to stimulation of glucose transport and activation of the mitogen-activated protein kinase cascade. The active insulin receptor phosphorylates tyrosine residues of intracellular proteins such as the insulin receptor substrate-1 (IRS-1) which acts as docking sites for molecules containing Src homology 2 (SH2) domains. One such molecule is phosphatidylinositol 3-kinase (PI 3-kinase) which becomes activated by binding to IRS-1. PI 3-kinase activity is required for the insulin-stimulation of glucose transport and glycogen synthesis. Grb2, a small adaptor molecule, can bind IRS-1 and, through the guanine nucleotide exchange factor Sos, leads to the activation of the small GTP binding protein Ras. Through a cascade of protein kinases, activation of Ras results in activation of the Erk 1 and 2 mitogen-activated protein kinases (MAPKs) which appear to control important nuclear and metabolic events. To investigate the role of the actin network in the propagation of insulin action leading to stimulation of glucose transport and the activation of the Erk MAPKs, we used the fungal metabolite cytochalasin D which disassembles the actin network. Actin disassembly abolished almost completely the ability of insulin to increase the rate of glucose transport into L6 muscle cells (myotubes) through prevention of the insulin-induced recruitment of glucose transporters to the plasma membrane which is the event that mediates the increase in the rate of transport. Actin disassembly did not affect either the insulin-mediated phosphorylation of IRS-1, the association of PI 3-kinase with this molecule, or the activation of IRS-1-associated PI 3-kinase. These results were also verified in another insulin responsive cell line, the 3T3-L1 adipocytes. In these cells, actin disassembly inhibited the insulin-induced recruitment of PI 3-kinase to intracellular membranes containing glucose transporters. Moreover, actin disassembly abolished the insulin-mediated phosphorylation of the Erk MAPKs. We conclude that the cellular actin network of insulin responsive cells is not required for the activation of PI 3-kinase but prevents its cellular redistribution. In contrast, intact actin filaments are essential for the propagation of insulin signals leading to the the activation of the MAPKs.</p>","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"52 ","pages":"257-71"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20153924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular architecture of the specialized axonal membrane at the node of Ranvier.","authors":"V Bennett,&nbsp;S Lambert,&nbsp;J Q Davis,&nbsp;X Zhang","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"52 ","pages":"107-20"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20154544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Capping actin filament growth: tropomodulin in muscle and nonmuscle cells.","authors":"V M Fowler","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Actin filament lengths are precisely regulated and very stable in the sarcomeres of striated muscle, in the erythrocyte membrane skeleton, and in cell protrusions such as microvilli in intestinal epithelial cells and stereocilia in hair cells of the inner ear. In contrast, in motile cells, actin filament lengths are dynamically regulated when cells extend lamellipodia. Control of actin filament lengths and dynamics in cells is expected to be achieved in part by capping proteins that prevent filament growth or shrinkage by blocking subunit exchange at both the fast growing (barbed) and slow growing (pointed) filament ends. Much is known about how barbed end capping proteins control actin filament assembly and length in many cells, but little is known about the significance of regulating actin filament assembly at the pointed end. Tropomodulin is the only known capping protein for the pointed ends of actin filaments and is a approximately 40-kD protein that is expressed in erythrocytes, striated muscle, lens fiber cells, some regions of the adult brain, as well as sensory neurons and epithelial cells of the inner ear. A related isoform (59% identical at the protein level) is expressed principally in neurons of both embryonic and adult brain. In striated muscle and in erythrocytes, tropomodulin is tightly associated with the actin filament pointed ends where it functions to maintain actin filament length in vivo (for recent reviews, see Fowler, 1996; Gregorio and Fowler, 1996). Unlike proteins that cap actin filament barbed ends, tropomodulin also binds tropomyosin and requires tropomyosin for tight capping of actin filament pointed ends. Mapping of functional domains on tropomodulin shows that the COOH-terminal end of tropomodulin is important for actin filament pointed end capping activity while the NH2-terminal portion of tropomodulin contains the tropomyosin binding domain. Searches of protein and EST databases for tropomodulin-like sequences reveal a number of proteins with homologies to both the tropomyosin binding and the actin filament capping portions of tropomodulin. In particular, we have identified a tropomodulin-like 64-kD protein that is principally expressed in smooth muscle cells. We anticipate that tropomodulin and this 64-kD protein are members of a larger family of tropomyosin and actin binding proteins that are responsible for capping actin filament pointed ends and regulating actin filament lengths in muscle and nonmuscle cells.</p>","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"52 ","pages":"79-89"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20154542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Actin-binding membrane proteins identified by F-actin blot overlays.","authors":"E J Luna,&nbsp;K N Pestonjamasp,&nbsp;R E Cheney,&nbsp;C P Strassel,&nbsp;T H Lu,&nbsp;C P Chia,&nbsp;A L Hitt,&nbsp;M Fechheimer,&nbsp;H Furthmayr,&nbsp;M S Mooseker","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Actin and associated proteins at the cytoskeleton-plasma membrane interface stabilize the membrane bilayer, control cell shape, and delimit specialized membrane domains. To identify membrane proteins that bind directly to F-actin, we have developed a blot overlay assay with 125I-labeled F-actin. In the soil amoebae, Dictyostelium discoideum, the major proteins reactive in this assay are p30a, a 34-kD peripheral membrane protein that is concentrated in filopodia and at sites of cell-cell adhesion, and ponticulin, a 17-kD transmembrane glycoprotein required for efficient chemotaxis and for control of pseudopod dynamics. Proteins with apparent molecular masses of approximately 34- and approximately 17-kD also are observed on F-actin blot overlays of many mammalian cell lines. However, in mammalian cells, the most prominent F-actin binding proteins in this assay exhibit apparent molecular masses of 78-, 80-, 81-, approximately 120-, and 205-kD. Bovine neutrophils contain the 78-, 81-, and 205-kD proteins, all of which co-isolate with a plasma membrane-enriched fraction. We have previously identified the 78-, 80-, and 81-kD proteins as moesin, radixin, and ezrin, respectively. These proteins, which are members of the protein 4.1 superfamily, colocalize with actin in cell surface extensions and have been implicated in the protrusion of microvilli, filopodia, and membrane ruffles. The 205-kD protein (p205) appears to be absent from current databases, and its characteristics are still under investigation. We here report that the 120-kD protein is drebrin, a submembranous actin-binding protein originally identified as a developmentally regulated brain protein. Thus, it appears that F-actin blot overlays provide an efficient assay for simultaneous monitoring of a subset of F-actin binding proteins, including p30a, ponticulin, moesin, radixin, ezrin, p205, and drebrin.</p>","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"52 ","pages":"3-18"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20154536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}