Regulation of microvillus structure

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dc.contributor.author Mooseker, M.S.
dc.contributor.author Graves, T.A.
dc.contributor.author Wharthon, K.A.
dc.contributor.author Falco, N.
dc.contributor.author Howe, C.L.
dc.date.accessioned 2019-06-03T07:00:41Z
dc.date.available 2019-06-03T07:00:41Z
dc.date.copyright 1980 en_US
dc.date.issued 2019-06-03
dc.identifier.issn 1540-8140 en_US
dc.identifier.uri http://hdl.handle.net/10725/10728
dc.description.abstract The bundle of filaments within microvilli of intestinal epithelial cells contains five major proteins including actin, calmodulin, and subunits of 105-, 95-, and 70-kdaltons. It has been previously shown (Howe, C. L., M. S. Mooseker, and T. A. Graves. 1980. Brush-border calmodulin: a major component of the isolated microvillus core. J. Cell Biol. 85: 916-923) that the addition of Ca++ (> 10(-6) M) to microvillus cores causes a rapid, drastic, but at least partially reversible disruption of this actin filament bundle. High-speed centrifugation of microvillus cores treated with Ca++ indicates that several core proteins are solubilized, including 30-50% of the actin and calmodulin, along with much of the 95- and 70-kdalton subunits. Gel filtration of such Ca++ extracts in the presence and absence of Ca++ indicates that microvillar actin "solated" by Ca++ is in an oligomeric state probably complexed with the 95-kdalton subunit. Removal of Ca++ results in the reassembly of F-actin, probably still complexed with 95-kdalton subunit, as determined by gel filtration, cosedimentation, viscometry, and electron microscopy. The 95-kdalton subunit (95K) was purified from Ca++ extracts by DEAE-Sephadex chromatography and its interaction with actin characterized by viscometry, cosedimentation, and EM in the presence and absence of Ca++. In the presence, but not absence, of Ca++, 95K inhibits actin assembly (50% inhibition at 1:50-60 95K to actin) and also reduces the viscosity of F-actin solutions. Similarly, sedimentation of actin is inhibited by 95K, but a small, presumably oligomeric actin- 95K complex formed in the presence of Ca++ is pelletable after long-term centrifugation. In the absence of Ca++, 95K cosediments with F-actin. EM of 95K-actin mixtures reveals that 95K "breaks" actin into small, filamentous fragments in the presence of Ca++. Reassembly of filaments occurs once Ca++ is removed. In the absence of Ca++, 95K has no effect on filament structure and, at relatively high ratios (1:2-6) of 95K to actin, this core protein will aggregate actin filaments into bundles. en_US
dc.language.iso en en_US
dc.title Regulation of microvillus structure en_US
dc.type Article en_US
dc.description.version Published en_US
dc.title.subtitle calcium-dependent solation and cross-linking of actin filaments in the microvilli of intestinal epithelial cells en_US
dc.author.school SOM en_US
dc.author.idnumber 201408989 en_US
dc.author.department N/A en_US
dc.description.embargo N/A en_US
dc.relation.journal Journal of Cell Biology en_US
dc.journal.volume 87 en_US
dc.journal.issue 3 en_US
dc.article.pages 809-822 en_US
dc.identifier.doi https://doi.org/10.1083/jcb.87.3.809 en_US
dc.identifier.ctation Mooseker, M. S., Graves, T. A., Wharton, K. A., Falco, N., & Howe, C. L. (1980). Regulation of microvillus structure: calcium-dependent solation and cross-linking of actin filaments in the microvilli of intestinal epithelial cells. The Journal of Cell Biology, 87(3), 809-822. en_US
dc.author.email nancy.chedid@lau.edu.lb en_US
dc.identifier.tou http://libraries.lau.edu.lb/research/laur/terms-of-use/articles.php en_US
dc.identifier.url http://jcb.rupress.org/content/87/3/809.abstract en_US
dc.author.affiliation Lebanese American University en_US

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