title: A conserved sequence in calmodulin regulated spectrin-associated protein 1 links its interaction with spectrin and calmodulin to neurite outgrowth.
abstract: Calmodulin regulated spectrin-associated protein 1 (CAMSAP1) is a vertebrate microtubule-binding protein, and a representative of a family of cytoskeletal proteins that arose with animals. We reported previously that the central region of the protein, which contains no recognized functional domain, inhibited neurite outgrowth when over-expressed in PC12 cells [Baines et al., Mol. Biol. Evol. 26 (2009), p. 2005]. The CKK domain (DUF1781) binds microtubules and defines the CAMSAP/ssp4 family of animal proteins (Baines et al. 2009). In the central region, three short well-conserved regions are characteristic of CAMSAP-family members. One of these, CAMSAP-conserved region 1 (CC1), bound to both βIIΣ1-spectrin and Ca(2+)/calmodulin in vitro. The binding of Ca(2+)/calmodulin inhibited spectrin binding. Transient expression of CC1 in PC12 cells inhibited neurite outgrowth. siRNA knockdown of CAMSAP1 inhibited neurite outgrowth in PC12 cells or primary cerebellar granule cells: this could be rescued in PC12 cells by wild-type CAMSAP1-enhanced green fluorescent protein, but not by a CC1 mutant. We conclude that CC1 represents a functional region of CAMSAP1, which links spectrin-binding to neurite outgrowth.
authors.affiliation: Department of Biosciences, University of Kent, Kent, UK.
authors.forename: Mikayala D A
authors.initials: MD
authors.lastname: King
authors.forename: Gareth W
authors.initials: GW
authors.lastname: Phillips
authors.forename: Paola A
authors.initials: PA
authors.lastname: Bignone
authors.forename: Nandini V L
authors.initials: NV
authors.lastname: Hayes
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Pinder
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Baines
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology; D002147:Calmodulin / Q000502:physiology*; D019295:Computational Biology; D017124:Conserved Sequence; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000235:genetics*; D009419:Nerve Tissue Proteins / Q000235:genetics*; D016501:Neurites / Q000502:physiology*; D016716:PC12 Cells; D010802:Phylogeny; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D013045:Species Specificity; D013049:Spectrin / Q000502:physiology*; D014162:Transfection
chemical_list: C586939:CAMSAP1 protein, rat; D002147:Calmodulin; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D034741:RNA, Small Interfering; D013049:Spectrin
keywords: cytoskeletal regulation; cytoskeleton; molecular evolution; nerve cells; protein domain; protein function