Effects of synaptic vesicles on actin polymerization

FEBS Letters

Valtorta, F.¹  Ceccaldi, P.E.¹  Chieregatt, E.¹  Benfenati, F.² 

[1] Dept. of Medical Pharmacology, ‘B. Ceccarelli’ and CNR Cellular and Molecular Pharmacology Centers and DIBIT S. Raffaele Scientific Institute, University of Milan, Milan, Italy;Dept. of Biomedical Sciences, Section of Physiology, University of Modena and Dept. of Experimental Medicine, University of Rome ‘Tor Vergata’, Rome, Italy

关键词: Synaptic vesicle;    Synapsin;    Nerve terminal;    Protein phosphorylation;    Cytoskeleton;    Actin;    CaM kinase II;    Ca2+/calmodulin-dependent protein kinase II;   

DOI  :  10.1016/S0014-5793(96)01240-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We have analyzed the effects of synaptic vesicles on actin polymerization by using a time-resolved spectrofluorometric assay. We have found that synaptic vesicles have complex effects on the kinetics of actin polymerization, which vary depending on whether the synaptic vesicle-specific phosphoprotein synapsin I is absent or present on their membrane. Synapsin I bound either to synaptic vesicles or to pure phospholipid vesicles exhibits phosphorylation-dependent actin-nucleating activity. Synaptic vesicles depleted of endogenous synapsin I decrease the rate and the final extent of actin polymerization, an effect which is not observed with pure phospholipid vesicles. Thus, the state of association of synapsin I with synaptic vesicles, which is modulated by its state of phosphorylation, may affect actin assembly and the physico-chemical characteristics of the synaptic vesicle microenvironment.

【 授权许可】

Unknown