FAP52, a Novel, SH3 Domain-containing Focal Adhesion Protein

• Published in: The Journal of biological chemistry 1997-09, Vol.272 (37), p.23278-23284
• Main Authors: Meriläinen, Jari, Lehto, Veli-Pekka, Wasenius, Veli-Matti
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Blotting, Northern; Brain Chemistry - genetics; Cell Adhesion; Cell Adhesion Molecules - genetics; Cell Adhesion Molecules - isolation & purification; Cell Compartmentation; Cells, Cultured; Chick Embryo; Cloning, Molecular; DNA Primers; Fluorescent Antibody Technique; Immunoblotting; Molecular Sequence Data; Phosphoproteins; Phosphoserine - analysis; Polymerase Chain Reaction; Precipitin Tests; Sequence Analysis, DNA; Sequence Homology, Amino Acid; src Homology Domains; Tissue Distribution
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.272.37.23278

Src-homology 3 (SH3) domain is a 60–70-amino acid motif present in a large variety of signal transduction and cytoskeletal proteins. We used reverse transcriptase-polymerase chain reaction with degenerate and specific primers and chicken brain mRNA to clone a cDNA that codes for a novel SH3 domain-containing protein. The sequence predicts a 448-amino acid polypeptide with a molecular mass of 51,971 daltons. In the amino terminus, it shows a very high propensity for α-helicity, suggesting coiled-coil and possibly a higher order oligomeric arrangement. In the carboxyl terminus, there is a unique SH3 sequence. In Northern blotting, a major 3.7-kilobase and a minor 7.2-kilobase transcript was detected in most chicken tissues. In immunofluorescence microscopy and immunoelectron microscopy on cultured chicken fibroblasts, the protein was localized to focal adhesions in which it showed a distinct codistribution with the focal adhesion proteins vinculin, talin, and paxillin. Phosphoamino acid analysis showed that in cultured chicken heart fibroblasts, the protein contains phosphoserine, but no phosphothreonine or phosphotyrosine, and that the phosphorylation is not dependent on fibronectin. We propose this protein the name FAP52, for Focal Adhesion Protein of52 kDa, and suggest that it forms part of the multimolecular complex constituting focal adhesion sites.