Gelsolin - evidence for a role in turnover of junction-related actin filaments in Sertoli cells
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| Authors: | Guttman, JA; Janmey, P; Vogl, AW |
| Year: | 2002 |
| Journal: | Journal of Cell Science 115: 499-505 Website |
| Title: | Gelsolin - evidence for a role in turnover of junction-related actin filaments in Sertoli cells |
| Abstract: | The gelsolin-phosphoinositide pathway may be part of the normal mechanism by which Sertoli cells regulate sperm release and turnover of the blood-testis barrier. The intercellular adhesion complexes (ectoplasmic specializations) involved with these two processes are tripartite structures consisting of the plasma membrane, a layer of actin filaments and a cistern of endoplasmic reticulum. Gelsolin is concentrated in these adhesion complexes. In addition, phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P-2) and phosphoinositide-specific phospholipase C are found in the structures. Treatment of isolated spermatid/junction complexes with exogenous phosphoinositide-specific phospholipase Q or with a synthetic peptide consisting of the PtdIns(4,5)P-2 binding region of gelsolin, results in the release of gelsolin and loss of actin from the adhesion complexes. We present a model for the disassembly of the actin layer of the adhesion complex that involves the hydrolysis of PtdIns(4,5)P-2 resulting in the release of gelsolin within the plaque. Further, we speculate that the hydrolysis of PtdIns(4,5)P-2 may result in a local Ca2+ surge via the action of inositol. triphosphate on junctional endoplasmic reticulum. This Ca2+ surge would facilitate the actin severing function of gelsolin within the adhesion complex. |
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