Ca2+-dependent interaction with calmodulin is conserved in the synapsin family: Identification of a high-affinity site

Nicol, Scott and Rahman, Daisy and Baines, Anthony J. (1997) Ca2+-dependent interaction with calmodulin is conserved in the synapsin family: Identification of a high-affinity site. Biochemistry, 36 (38). pp. 11487-11495. ISSN 0006-2960. (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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The synapsins are a family of proteins associated with small synaptic vesicles that are implicated in synaptic maintenance and in the supply of vesicles for exocytosis. They are well characterized as substrates for protein kinases, and one class of synapsin, synapsin I, has been shown to bind, and be regulated by, calmodulin. A representative of the synapsin II class is now shown to bind calmodulin. Optical biosensor assays of Ca2+-dependent calmodulin binding to recombinant rat synapsin IIb indicated an apparent K-D for calmodulin of 31 +/- 5 nM. Phosphorylation at Ser 10 increased the rates of calmodulin association (by a factor of 10) and dissociation (by a factor of 20). Fragment analysis and predictions from the sequence indicated two potential calmodulin binding sequences in the conserved central (C) domain. Peptides representing these sequences (residues 122-143 and 313-334 in synapsin IIb) were synthesized. Peptide 122-143 was found to bind calmodulin (K-D 32 +/- 10 nM) and inhibit interaction of synapsin IIb with calmodulin. The interaction of peptide 313-334 was much weaker. Sequences similar to residues 122-143 are present in all published synapsin sequences. Calmodulin binding by synapsins seems not to be confined to mammals: a recombinant Drosophila synapsin 1 fragment containing part of the C-domain showed Ca2+-dependent binding to mammalian calmodulin. We conclude that calmodulin binding to synapsins is likely to be a general aspect of regulation of synaptic function.

Item Type: Article
Additional information: This work was supported by the Medical Research Council (U.K.). An equipment grant from the Wellcome Trust is acknowledged. , * To whom correspondence should be addressed. Telephone: +44 1227 823462. Fax: +44 1227 763912. Email:
Subjects: Q Science
Q Science > QH Natural history > QH301 Biology
Divisions: Faculties > Science Technology and Medical Studies > School of Biosciences
Depositing User: M.A. Ziai
Date Deposited: 17 Apr 2009 17:11
Last Modified: 17 Apr 2014 12:54
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