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Effects of synaptic vesicles on actin polymerization
Author(s) -
Chieregatt E.,
Ceccaldi P.E.,
Benfenati F.,
Valtorta F.
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(96)01240-9
Subject(s) - synaptic vesicle , vesicle , synapsin i , synapsin , biophysics , synaptic augmentation , chemistry , actin , microbiology and biotechnology , neurotransmission , biology , biochemistry , membrane , receptor
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.