Molecular cloning and functional expression of chromaffin cell scinderin indicates that it belongs to the family of Ca(2+)-dependent F-actin severing proteins.

Scinderin is a Ca(2+)-dependent actin filament severing protein present in chromaffin cells, platelets and a variety of secretory cells. It has been suggested that scinderin is involved in chromaffin cell F-actin dynamics and that this actin network controls the delivery of secretory vesicles to plasma membrane exocytotic sites. Moreover, scinderin redistribution and activity may be regulated by pH and Ca2+ in resting and stimulated cells. Here we describe the molecular cloning, the nucleotide sequence and the expression of bovine chromaffin cell scinderin cDNA. The fusion protein obtained cross-reacts with native scinderin antibodies and binds phosphatidylserine (PS), phosphatidylinositol 4,5-bisphosphate (PIP2) and actin in a Ca(+)-dependent manner. Antibodies raised against the fusion protein produced the same cellular staining patterns for scinderin as anti-native scinderin. Nucleotide and amino acid sequence analysis indicate that scinderin has six domains each containing three internal sequence motifs, two actin and two PIP2 binding sites and has 63 and 53% homology with gelsolin and villin. These data indicate that scinderin is a novel member of the family of Ca(2+)-dependent F-actin severing proteins which includes gelsolin and villin.