Society of General Physiologists series最新文献

{"title":"The generation of protein isoform diversity by alternative RNA splicing.","authors":"D M Helfman","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"49 ","pages":"105-15"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18939403","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 evolution of K+ channels in primitive eukaryotes.","authors":"T Jegla,&nbsp;L Salkoff","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Cnidarians and ciliate protozoans represent evolutionary interesting phylogenetic groups for the study of K+ channel evolution. Cnidaria is a primitive metazoan phylum consisting of simple diploblast organisms which have few tissue types such as jellyfish, hydra, sea anemones, and corals. Their divergence from the rest of the metazoan line may predate the radiation of the major triploblast phyla by several hundred million years (Morris, 1993). Cnidarians are the most primitive metazoans to have an organized nervous system. Thus, comparing K+ channels cloned from cnidarians to those cloned from more advanced metazoans may reveal which types of K+ channel are most fundamental to electrical excitability in the nervous system. In contrast, channels in ciliate protozoans such as Paramecium may not have been designed to send electrical signals between cells, but simply to control the behavior, such as an avoidance reaction, of a single cell. Hence, comparing cloned Paramecium K+ channels to K+ channels cloned from cnidarians and other metazoans may reveal which types of K+ channel are most fundamental to electrical excitability in eukaryotes, and which K+ channels are specialized for neuronal signaling. Potassium channels are involved in a diversity of tasks and are universally present in eukaryotes. K+ channels set the resting membrane potentials of most metazoan and protozoan cells and are fundamental components of membrane electrical activity in virtually all eukaryotic systems. These channels control the shape, duration and frequency of metazoan action potentials and are known to participate in the action potentials of protozoans, fungi and plants as well (Hille, 1992). Voltage-clamp recordings have shown that a various assortment of voltage-gated K+ channels as well as Ca(2+)-activated K+ channels are widespread in eukaryotes (Hille, 1992). Thus, K+ channels appear to be crucial to behavioral responses in all classes of eukaryotes, including locomotion in metazoans and protozoans, and rapid growth responses and cell shape changes in plants. K+ channel diversity is by far the greatest in metazoans, which have made a strong commitment to electrically excitable cellular networks. There is an apparent need for a great diversity of K+ channel subtypes in these metazoans. Over 50 K+ channel sequences from many distinct gene families have been reported so far, and all but two (both from plants) have been found in triploblast metazoans. The complex needs of neuronal integration and neuromuscular transmission in triploblasts require exquisite control of cellular excitability. This is in large part achieved by an extensive and diverse set of K+ channels.(ABSTRACT TRUNCATED AT 250 WORDS)</p>","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"49 ","pages":"213-22"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18939410","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":"The connexins and their family tree.","authors":"M V Bennett,&nbsp;X Zheng,&nbsp;M L Sogin","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The connexins, gap junction forming proteins, are encoded by a gene family. Sequence comparisons reveal regions of conservation with functional implications for voltage dependence of junctional conductance, junction formation and regulation by phosphorylation. The best connexin tree shows that most gene duplications giving rise to the family occurred early in or before vertebrate divergence. The topology of most deep branches of the tree is uncertain. Evolutionary rates vary for different paralogous connexin genes.</p>","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"49 ","pages":"223-33"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18939411","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 clocks are not as bad as you think.","authors":"W M Fitch,&nbsp;F J Ayala","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"49 ","pages":"3-12"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18936437","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":"The evolution of the chicken sarcomeric myosin heavy chain multigene family.","authors":"E Bandman,&nbsp;L A Moore,&nbsp;M J Arrizubieta,&nbsp;W E Tidyman,&nbsp;L Herman,&nbsp;M Wick","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>This manuscript describes the chicken sarcomeric myosin heavy chain (MyHC) multigene family and how it differs from the sarcomeric MyHC multigene families of other vertebrates. Data is discussed that suggests the chicken fast MyHC multigene family has undergone recent expansion subsequent to the divergence of avians and mammals, and has been subjected to multiple gene conversion-like events. Similar to human and rodent MyHC multigene families, the chicken multigene family contains sarcomeric MyHC genes that are differentially regulated in developing embryonic, fetal, and neonatal muscles. However, unlike mammalian genes, chicken fast MyHC genes expressed in developing muscles are also expressed in mature muscle fibers as well. The potential significance of conserved and divergent sequences with the MyHC rod domain of five fast chicken isoforms that have been cloned and sequenced is also discussed.</p>","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"49 ","pages":"129-39"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18939405","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":"Reconstructing the history of evolutionary processes using maximum likelihood.","authors":"M J Sanderson","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"49 ","pages":"13-26"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18939406","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 evolution of the myosin superfamily: application of phylogenetic techniques to cell biological questions.","authors":"H V Goodson","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>We have used distance matrix and maximum parsimony methods to study the evolutionary relationships between members of the myosin superfamily of molecular motors. Amino acid sequences of the conserved core of the motor region were used in the analysis. Our results show that myosins can be divided into at least three main classes, with two types of unconventional myosin being no more related to each other than they are to conventional myosin. Myosins have traditionally been classified as conventional or unconventional, with many of the unconventional myosin proteins thought to be distributed in a narrow range of organisms. We find that members of all three of these main classes are likely to be present in most (or all) eukaryotes. Three proteins do not cluster within the three main groups and may each represent additional classes. The structure of the trees suggests that these ungrouped proteins and some of the subclasses of the main classes are also likely to be widely distributed, implying that most eukaryotic cells contain many different myosin proteins. The groupings derived from phylogenetic analysis of myosin head sequences agree strongly with those based on tail structure, developmental expression, and (where available) enzymology, suggesting that specific head sequences have been tightly coupled to specific tail sequences throughout evolution. Analysis of the relationships within each class has interesting implications. For example, smooth muscle myosin and striated muscle myosin seem to have independently evolved from nonmuscle myosin. Furthermore, brush border myosin I, a type of protein initially thought to be specific to specialized metazoan tissues, probably has relatives that are much more broadly distributed.</p>","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"49 ","pages":"141-57"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18939407","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":"Diversity of myosin-based motility: multiple genes and functions.","authors":"A Weiss,&nbsp;D C Mayer,&nbsp;L A Leinwand","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"49 ","pages":"159-71"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18939408","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 evolution of the calcium-transporting ATPases analyzed by the maximum parsimony method.","authors":"Y Song,&nbsp;D Fambrough","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"49 ","pages":"271-83"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18936436","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":"To tree the truth: biological and numerical simulation of phylogeny.","authors":"D M Hillis,&nbsp;J P Huelsenbeck","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":76550,"journal":{"name":"Society of General Physiologists series","volume":"49 ","pages":"55-67"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18936439","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}