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.

Effects of synaptic vesicles on actin polymerization / Chieregatti, E; Ceccaldi, P. E; Benfenati, F; Valtorta, Flavia. - In: FEBS LETTERS. - ISSN 0014-5793. - 398:2-3(1996), p. 211-6.

Effects of synaptic vesicles on actin polymerization

VALTORTA, FLAVIA
Ultimo
1996-01-01

Abstract

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.
1996
Actins; Animals; Cattle; Kinetics; Membranes, Artificial; Osmolar Concentration; Phosphorylation; Polymers; Rats; Spectrometry, Fluorescence; Synapsins; Synaptic Vesicles; Viscosity
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11768/61319
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