Recombinant scinderin enhances exocytosis, an effect blocked by two scinderin-derived actin-binding peptides and PIP sub(2)

• Published in: Neuron (Cambridge, Mass.) Mass.), 1996-01, Vol.17 (2), p.287-296
• Main Authors: Zhang, L, Marcu, M G, Nau-Staudt, K, Trifaro, J-M
• Format: Article
• Language: English
• ISSN: 0896-6273

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 super(2+)-dependent F-actin-severing protein) potentiated Ca super(2+)-evoked F-actin disassembly and exocytosis in permeabilized chromaffin cells, an effect blocked by peptides Sc-ABP sub(1) and Sc-ABP sub(2) (with sequences corresponding to two actin-binding sites of scinderin), exogenous gamma -actin, or phosphatidylinositol 4,5-bisphosphate (PIP sub(2)). PIP sub(2) effect was blocked by peptide Sc-PIP sub(2)BP (with sequence corresponding to a PIP sub(2)-binding site of scinderin). Truncated scinderin sub(254-715) (lacking actin-severing domains) did not potentiate exocytosis. Sc-ABP sub(1), Sc-ABP sub(2), 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.