Regulation of cytoskeletal protein organization and expression in human granulosa cells in response to gonadotropin treatment.
The organization and expression of the major cytoskeletal protein systems and of several cytoskeleton-associated proteins were analyzed in human granulosa cells obtained from preovulatory follicles in the course of an in vitro fertilization program. The cells were cultured in medium containing 5% fetal calf serum in the absence or presence of gonadotropins. Within several hours after the addition of hCG to cultured human granulosa cells, the cells acquired a rounded and aggregated morphology with numerous thin and long processes. Cells cultured without the gonadotropin had a flat and extended morphology on the substrate, with a well developed stress fiber system and numerous large vinculin-containing adhesion plaques. The [35S]methionine-labeled protein pattern of hCG-treated cells obtained by two-dimensional isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a 7- to 10-fold decrease in the synthesis of vinculin and the nonmuscle tropomyosin isoforms, and a 2- to 4-fold decrease in the synthesis of alpha-actinin and actin, without a comparable change in alpha- and beta-tubulin synthesis. In the absence of gonadotropins, human granulosa cells synthesized both the intermediate filament (IF) protein vimentin and cytokeratin-type IF proteins 8 and 18 and, to a lesser extent, cytokeratins 7 and 19. By immunofluorescence, both type of IF networks were detected in untreated cells, while hCG-treated cells synthesized and contained only vimentin-type IF networks. Thus, maintenance of the steroidogenic capacity in the presence of gonadotropins in human granulosa-luteal cells involves specific changes in cell shape and in both the organization and the expression of the microfilament and IF systems.
Ben-Ze'ev
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Department of Genetics, Weizmann Institute of Science, Rehovot, Israel.
Amsterdam
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D000199:Actins / Q000096:biosynthesis; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D003598:Cytoskeletal Proteins / Q000096:biosynthesis* / Q000302:isolation & purification; D005260:Female; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D008840:Microfilament Proteins / Q000096:biosynthesis; D009124:Muscle Proteins / Q000096:biosynthesis; D011374:Progesterone / Q000378:metabolism; D016596:Vinculin
D000199:Actins; D006063:Chorionic Gonadotropin; D003598:Cytoskeletal Proteins; D008840:Microfilament Proteins; D009124:Muscle Proteins; D016596:Vinculin; D011374:Progesterone