ABSTRACT
PACSIN 1/syndapin 1 was originally identified by its drastic expression decrease during CNS repair processes and by virtue o f its binding to the GTPase dynamin. The three family members play important roles as accessory proteins in clathrin-mediated endocytosis. They differ in tissue distribution and developmental expression, but share many interaction partners and their ability to bind to lipid surfaces. Besides contributing to membrane deforma tion PACSIN proteins play a key function as adaptor proteins, coupling various components o f the clathrin-assisted uptake with the actin polymerization machinery. Although many molecules are able to link both processes, the role o f PACSINs in recognizing and regulating specific cargo molecules is only now beginning to be understood. Recent functional studies using a wide range o f cells and tissues have revealed a crucial role for PACSIN proteins as modulators o f receptor function by controlling their internalization and/or recycling. Current knowledge regarding PACSIN functions is reviewed here.