Targeting protein phosphatase 1 (PP1) to the actin cytoskeleton: the neurabin I/PP1 complex regulates cell morphology.
Journal Article (Journal Article)
Neurabin I, a neuronal actin-binding protein, binds protein phosphatase 1 (PP1) and p70 ribosomal S6 protein kinase (p70S6K), both proteins implicated in cytoskeletal dynamics. We expressed wild-type and mutant neurabins fused to green fluorescent protein in Cos7, HEK293, and hippocampal neurons. Biochemical and cellular studies showed that an N-terminal F-actin-binding domain dictated neurabin I localization at actin cytoskeleton and promoted disassembly of stress fibers. Deletion of the C-terminal coiled-coil and sterile alpha motif domains abolished neurabin I dimerization and induced filopodium extension. Immune complex assays showed that neurabin I recruited an active PP1 via a PP1-docking sequence,(457)KIKF(460). Mutation of the PP1-binding motif or PP1 inhibition by okadaic acid and calyculin A abolished filopodia and restored stress fibers in cells expressing neurabin I. In vitro and in vivo studies suggested that the actin-binding domain attenuated protein kinase A (PKA) phosphorylation of neurabin I. Modification of a major PKA site, serine-461, impaired PP1 binding. Finally, p70S6K was excluded from neurabin I/PP1 complexes and required the displacement of PP1 for recruitment to neurabin I. These studies provided new insights into the assembly and regulation of a neurabin I/PP1 complex that controls actin rearrangement to promote spine development in mammalian neurons.
Full Text
Duke Authors
Cited Authors
- Oliver, CJ; Terry-Lorenzo, RT; Elliott, E; Bloomer, WAC; Li, S; Brautigan, DL; Colbran, RJ; Shenolikar, S
Published Date
- July 2002
Published In
Volume / Issue
- 22 / 13
Start / End Page
- 4690 - 4701
PubMed ID
- 12052877
Pubmed Central ID
- PMC133892
International Standard Serial Number (ISSN)
- 0270-7306
Digital Object Identifier (DOI)
- 10.1128/MCB.22.13.4690-4701.2002
Language
- eng
Conference Location
- United States