Cloning and Characterization of Cell Adhesion Kinase , a Novel Protein-tyrosine Kinase of the Focal Adhesion Kinase Subfamily

doi:10.1074/jbc.270.36.21206

Cloning and Characterization of Cell Adhesion Kinase , a Novel Protein-tyrosine Kinase of the Focal Adhesion Kinase Subfamily (*)

From the (1)Department of Biochemistry, Cancer Research Institute, and the
(2)Department of Pathology, Sapporo Medical University School of Medicine, South-1, West-17, Chuo-Ku, Sapporo 060, Japan

^§ To whom correspondence should be addressed:
Dept. of Biochemistry, Cancer Research Institute, Sapporo Medical University School of Medicine, South-1, West-17, Chuo-Ku, Sapporo 060, Japan.
Tel.: 81-11-611-2111 (ext. 2380); Fax: 81-11-612-5861.

Abstract

A second protein-tyrosine kinase (PTK) of the focal adhesion kinase (FAK) subfamily, cell adhesion kinase β (CAKβ), was identified by cDNA cloning. The rat CAKβ is a 115.7-kDa PTK that contains N- and C-terminal domains of 418 and 330 amino acid residues besides the central kinase domain. The rat CAKβ has a homology with mouse FAK over their entire lengths except for the extreme N-terminal 88 residues and shares 45% overall sequence identity (60% identical in the catalytic domain), which indicates that CAKβ is a protein structurally related to but different from FAK. The CAKβ gene is less evenly expressed in a variety of rat organs than the FAK gene. Anti-CAKβ antibody immunoprecipitated a 113-kDa protein from rat brain, 3Y1 fibroblasts, and COS-7 cells transfected with CAKβ cDNA. The tyrosine-phosphorylated state of CAKβ was not reduced on trypsinization, nor enhanced in response to plating 3Y1 cells onto fibronectin. CAKβ localized to sites of cell-to-cell contact in COS-7 transfected with CAKβ cDNA, in which FAK was found at the bottom of the cells. Thus, CAKβ is a PTK possibly participating in the signal transduction regulated by cell-to-cell contacts.

Footnotes

↵* The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The nucleotide sequences reported in this paper have been submitted to the GSDB, DDBJ, EMBL, and NCBI nucleotide sequence data bases with accession numbers D45854 [GenBank]and D45853[GenBank].
↵¹ The abbreviations used are:

PTKs

protein-tyrosine kinases

FAK

focal adhesion kinase

CAKβ

cell adhesion kinase β

PCR

polymerase chain reaction

SH-2

Src homology 2

SH-3

Src-homology 3

PAGE

polyacrylamide gel electrophoresis

PVDF

polyvinylidene difluoride

PBS

phosphate-buffered saline.
↵²T. Sasaki, K. Nagura, and H. Sasaki, manuscript in preparation.
- Received April 5, 1995.