RGD Reference Report - Phosphorylation of septin 3 on Ser-91 by cGMP-dependent protein kinase-I in nerve terminals. - Rat Genome Database

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Phosphorylation of septin 3 on Ser-91 by cGMP-dependent protein kinase-I in nerve terminals.

Authors: Xue, J  Milburn, PJ  Hanna, BT  Graham, ME  Rostas, JA  Robinson, PJ 
Citation: Xue J, etal., Biochem J. 2004 Aug 1;381(Pt 3):753-60.
RGD ID: 2317330
Pubmed: PMID:15107017   (View Abstract at PubMed)
PMCID: PMC1133885   (View Article at PubMed Central)
DOI: DOI:10.1042/BJ20040455   (Journal Full-text)

The septins are a family of GTPase enzymes required for cytokinesis and play a role in exocytosis. Among the ten vertebrate septins, Sept5 (CDCrel-1) and Sept3 (G-septin) are primarily concentrated in the brain, wherein Sept3 is a substrate for PKG-I (cGMP-dependent protein kinase-I) in nerve terminals. There are two motifs for potential PKG-I phosphorylation in Sept3, Thr-55 and Ser-91, but phosphoamino acid analysis revealed that the primary site is a serine. Derivatization of phosphoserine to S-propylcysteine followed by N-terminal sequence analysis revealed Ser-91 as a major phosphorylation site. Tandem MS revealed a single phosphorylation site at Ser-91. Substitution of Ser-91 with Ala in a synthetic peptide abolished phosphorylation. Mutation of Ser-91 to Ala in recombinant Sept3 also abolished PKG phosphorylation, confirming that Ser-91 is the major site in vitro. Antibodies raised against a peptide containing phospho-Ser-91 detected phospho-Sept3 only in the cytosol of nerve terminals, whereas Sept3 was located in a peripheral membrane extract. Therefore Sept3 is phosphorylated on Ser-91 in nerve terminals and its phosphorylation may contribute to the regulation of its subcellular localization in neurons.



Gene Septin3 septin 3 Rattus norvegicus