|
|
|
|
|
|
|
||
J. Cell Biol.,
Volume 143, Number 5, November 30, 1998 1227-1238
* Department of Molecular Biology and Biochemistry, Osaka University Medical School, Suita 565-0871, Japan; and We isolated two novel actin filament
(F-actin)-binding proteins from rat brain and rat 3Y1
fibroblast. They were splicing variants, and we named
brain big one b-nexilin and fibroblast small one s-nexilin. b-Nexilin purified from rat brain was a protein of
656 amino acids (aa) with a calculated molecular weight
of 78,392, whereas s-nexilin, encoded by the cDNA isolated from rat 3Y1 cells by the reverse transcriptase-PCR method, was a protein of 606 aa with a calculated
molecular weight of 71,942. b-Nexilin had two F-actin-
binding domains (ABDs) at the NH2-terminal and middle regions, whereas s-nexilin had one ABD at the middle region because 64 aa residues were deleted and 14 aa residues were inserted in the first NH2-terminal
ABD of b-nexilin, and thereby the first ABD lost its activity. b- and s-nexilins bound along the sides of F-actin,
but only b-nexilin showed F-actin cross-linking activity. b-Nexilin was mainly expressed in brain and testis,
whereas s-nexilin was mainly expressed in testis, spleen,
and fibroblasts, such as rat 3Y1 and mouse Swiss 3T3
cells, but neither b- nor s-nexilin was detected in liver,
kidney, or cultured epithelial cells. An immunofluorescence microscopic study revealed that s-nexilin was colocalized with vinculin, talin, and paxillin at cell-
matrix adherens junction (AJ) and focal contacts, but
not at cell-cell AJ, in 3Y1 cells. Overexpressed b- and
s-nexilins were localized at focal contacts but not at
cell-cell AJ. These results indicate that nexilin is a novel
F-actin-binding protein localized at cell-matrix AJ.
Takai Biotimer Project, ERATO, Japan Science and Technology Corporation (c/o JCR Pharmaceuticals Co., Ltd.), Kobe
651-2241, Japan
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
