Identification of in vitro phosphorylation sites in the growth cone protein SCG10. Effect Of phosphorylation site mutants on microtubule-destabilizing activity.
Details
Serval ID
serval:BIB_EEA709B7695D
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Identification of in vitro phosphorylation sites in the growth cone protein SCG10. Effect Of phosphorylation site mutants on microtubule-destabilizing activity.
Journal
Journal of Biological Chemistry
ISSN
0021-9258 (Print)
ISSN-L
0021-9258
Publication state
Published
Issued date
1998
Volume
273
Number
14
Pages
8439-8446
Language
english
Abstract
SCG10 is a neuron-specific, membrane-associated protein that is highly concentrated in growth cones of developing neurons. Previous studies have suggested that it is a regulator of microtubule dynamics and that it may influence microtubule polymerization in growth cones. Here, we demonstrate that in vivo, SCG10 exists in both phosphorylated and unphosphorylated forms. By two-dimensional gel electrophoresis, two phosphoisoforms were detected in neonatal rat brain. Using in vitro phosphorylated recombinant protein, four phosphorylation sites were identified in the SCG10 sequence. Ser-50 and Ser-97 were the target sites for protein kinase A, Ser-62 and Ser-73 for mitogen-activated protein kinase and Ser-73 for cyclin-dependent kinase. We also show that overexpression of SCG10 induces a disruption of the microtubule network in COS-7 cells. By expressing different phosphorylation site mutants, we have dissected the roles of the individual phosphorylation sites in regulating its microtubule-destabilizing activity. We show that nonphosphorylatable mutants have increased activity, whereas mutants in which phosphorylation is mimicked by serine-to-aspartate substitutions have decreased activity. These data suggest that the microtubule-destabilizing activity of SCG10 is regulated by phosphorylation, and that SCG10 may link signal transduction of growth or guidance cues involving serine/threonine protein kinases to alterations of microtubule dynamics in the growth cone.
Keywords
Amino Acid Sequence, Animals, Brain/metabolism, Brain/ultrastructure, Carrier Proteins, Electrophoresis, Gel, Two-Dimensional, Membrane Proteins, Microtubules/metabolism, Microtubules/ultrastructure, Molecular Sequence Data, Mutation, Nerve Growth Factors/genetics, Nerve Growth Factors/metabolism, Phosphoproteins/genetics, Phosphoproteins/metabolism, Phosphorylation, Rats, Rats, Wistar
Pubmed
Web of science
Open Access
Yes
Create date
24/01/2008 15:34
Last modification date
20/08/2019 17:16