重组丝切蛋白增强胞吐作用，该效应被两种源自丝切蛋白的肌动蛋白结合肽和磷脂酰肌醇-4,5-二磷酸所阻断。

Recombinant scinderin enhances exocytosis, an effect blocked by two scinderin-derived actin-binding peptides and PIP2.

作者信息

Zhang L, Marcu M G, Nau-Staudt K, Trifaró J M

机构信息

Department of Pharmacology, Faculty of Medicine, University of Ottawa, Ontario, Canada.

出版信息

Neuron. 1996 Aug;17(2):287-96. doi: 10.1016/s0896-6273(00)80160-9.

DOI:10.1016/s0896-6273(00)80160-9

PMID:8780652

Abstract

The cortical F-actin cytoskeleton represents a negative control for secretion, and it must be locally disassembled to allow chromaffin vesicle exocytosis. Recombinant scinderin (a Ca(2+)-dependent F-actin-severing protein) potentiated Ca(2+)-evoked F-actin disassembly and exocytosis in permeabilized chromaffin cells, an effect blocked by peptides Sc-ABP1 and Sc-ABP2 (with sequences corresponding to two actin-binding sites of scinderin), exogenous gamma-actin, or phosphatidylinositol 4,5-bisphosphate (PIP2). PIP2 effect was blocked by peptide Sc-PIP2BP (with sequence corresponding to a PIP2-binding site of scinderin). Truncated scinderin254-715 (lacking actin-severing domains) did not potentiate exocytosis. Sc-ABP1, Sc-ABP2, and gamma-actin also inhibited exocytosis in the absence of recombinant scinderin, suggesting an inhibition of endogenous scinderin. Results suggest that scinderin-evoked cortical F-actin disassembly is required for secretion and that scinderin is an important component of the exocytotic machinery.

摘要

皮质F-肌动蛋白细胞骨架是分泌的负调控因子，其必须在局部解聚才能使嗜铬囊泡发生胞吐作用。重组分裂蛋白（一种Ca(2+)依赖性F-肌动蛋白切割蛋白）增强了通透化嗜铬细胞中Ca(2+)诱发的F-肌动蛋白解聚和胞吐作用，该效应被Sc-ABP1和Sc-ABP2肽段（其序列对应于分裂蛋白的两个肌动蛋白结合位点）、外源性γ-肌动蛋白或磷脂酰肌醇4,5-二磷酸（PIP2）所阻断。PIP2的效应被Sc-PIP2BP肽段（其序列对应于分裂蛋白的一个PIP2结合位点）所阻断。截短的分裂蛋白254-715（缺乏肌动蛋白切割结构域）不能增强胞吐作用。在没有重组分裂蛋白的情况下，Sc-ABP1、Sc-ABP2和γ-肌动蛋白也抑制胞吐作用，提示对内源性分裂蛋白的抑制。结果表明，分裂蛋白诱发的皮质F-肌动蛋白解聚是分泌所必需的，且分裂蛋白是胞吐机制的重要组成部分。