Interaction of PKN with alpha-actinin

• Published in: The Journal of biological chemistry 1997-02, Vol.272 (8), p.4740-4746
• Main Authors: Mukai, H, Toshimori, M, Shibata, H, Takanaga, H, Kitagawa, M, Miyahara, M, Shimakawa, M, Ono, Y
• Format: Article
• Language: English
• Subjects: Actinin - metabolism; Binding Sites; DNA, Complementary - analysis; DNA, Complementary - genetics; Humans; Protein Kinase C; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - metabolism; Protein-Tyrosine Kinases - genetics; Protein-Tyrosine Kinases - metabolism; Substrate Specificity
• ISSN: 0021-9258
• DOI: 10.1074/jbc.272.8.4740

PKN is a fatty acid- and Rho-activated serine/threonine protein kinase, having a catalytic domain homologous to protein kinase C family. To identify components of the PKN-signaling pathway such as substrates and regulatory proteins of PKN, the yeast two-hybrid strategy was employed. Using the N-terminal region of PKN as a bait, cDNAs encoding actin cross-linking protein alpha-actinin, which lacked the N-terminal actin-binding domain, were isolated from human brain cDNA library. The responsible region for interaction between PKN and alpha-actinin was determined by in vitro binding analysis using the various truncated mutants of these proteins. The N-terminal region of PKN outside the RhoA-binding domain was sufficiently shown to associate with alpha-actinin. PKN bound to the third spectrin-like repeats of both skeletal and non-skeletal muscle type alpha-actinin. PKN also bound to the region containing EF-hand-like motifs of non-skeletal muscle type alpha-actinin in a Ca2+-sensitive manner and bound to that of skeletal muscle type alpha-actinin in a Ca2+-insensitive manner. alpha-Actinin was co-immunoprecipitated with PKN from the lysate of COS7 cells transfected with both expression constructs for PKN and alpha-actinin lacking the actin-binding domain. In vitro translated full-length alpha-actinin containing the actin-binding site hardly bound to PKN, but the addition of phosphatidylinositol 4, 5-bisphosphate, which is implicated in actin reorganization, stimulated the binding activity of the full-length alpha-actinin with PKN. We therefore propose that PKN is linked to the cytoskeletal network via a direct association between PKN and alpha-actinin.