Tensin is a focal-adhesion molecule that binds to actin filaments and interacts with phosphotyrosine-containing proteins. To analyse tensin's function in mammals, we have cloned tensin cDNAs from human and cow. The isolated approx. 7.7-kb human cDNA contains an open reading frame encoding 1735 amino acid residues. The amino acid sequence of human tensin shares 60% identity with chicken tensin, and contains all the structural features described previously in chicken tensin. This includes the actin-binding domains, the Src homology domain 2, and the region similar to a tumour suppressor, PTEN. Two major differences between human and chicken tensin are (i) the lack of the first 54 residues present in chicken tensin, and (ii) the addition of 34- and 38-residue inserts in human and bovine tensin. In addition, our interspecies sequencing data have uncovered the presence of a glutamine/CAG repeat that appears to have expanded in the course of evolution. Northern-blot analysis reveals a 10-kb message in most of the human tissues examined. An additional 9-kb message is detected in heart and skeletal muscles. The molecular mass predicted from the human cDNA is 185kDa, although both endogenous and recombinant human tensin migrate as 220-kDa proteins on SDS/PAGE. The discrepancy is due to the unusually low electrophoretic mobility of the central region of the tensin polypeptide (residues 306–981). A survey of human prostate and breast cancer cell lines by Western-blot analysis shows a lack of tensin expression in most cancer cell lines, whereas these lines express considerable amounts of focal-adhesion molecules such as talin and focal-adhesion kinase. Finally, tensin is rapidly cleaved by a focal-adhesion protease, calpain II. Incubation of cells with a calpain inhibitor, MDL, prevented tensin cleavage and induced morphological change in these cells, suggesting that cleavage of tensin and other focal-adhesion constituents by calpain disrupts maintenance of normal cell shape.
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Research Article| October 10 2000
Molecular characterization of human tensin
Huaiyang CHEN ;
Akiko ISHII ;
Wai-Keung WONG ;
Lan Bo CHEN ;
Su Hao LO
Su Hao LO 1
*Center for Tissue Regeneration and Repair, Department of Orthopaedic Surgery, The University of California-Davis, 4635 Second Avenue, Sacramento, CA 95817, U.S.A.
1To whom correspondence should be addressed (e-mail email@example.com).
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Huaiyang CHEN, Akiko ISHII, Wai-Keung WONG, Lan Bo CHEN, Su Hao LO; Molecular characterization of human tensin. Biochem J 15 October 2000; 351 (2): 403–411. doi: https://doi.org/10.1042/bj3510403
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