| First Author | Lin C | Year | 2013 |
| Journal | J Biol Chem | Volume | 288 |
| Issue | 41 | Pages | 29403-13 |
| PubMed ID | 23996002 | Mgi Jnum | J:204536 |
| Mgi Id | MGI:5532779 | Doi | 10.1074/jbc.M113.470708 |
| Citation | Lin C, et al. (2013) Cypher/ZASP is a novel A-kinase anchoring protein. J Biol Chem 288(41):29403-13 |
| abstractText | PKA signaling is important for the post-translational modification of proteins, especially those in cardiomyocytes involved in cardiac excitation-contraction coupling. PKA activity is spatially and temporally regulated through compartmentalization by protein kinase A anchoring proteins. Cypher/ZASP, a member of PDZ-LIM domain protein family, is a cytoskeletal protein that forms multiprotein complexes at sarcomeric Z-lines. It has been demonstrated that Cypher/ZASP plays a pivotal structural role in the structural integrity of sarcomeres, and several of its mutations are associated with myopathies including dilated cardiomyopathy. Here we show that Cypher/ZASP, interacting specifically with the type II regulatory subunit RIIalpha of PKA, acted as a typical protein kinase A anchoring protein in cardiomyocytes. In addition, we show that Cypher/ZASP itself was phosphorylated at Ser(265) and Ser(296) by PKA. Furthermore, the PDZ domain of Cypher/ZASP interacted with the L-type calcium channel through its C-terminal PDZ binding motif. Expression of Cypher/ZASP facilitated PKA-mediated phosphorylation of the L-type calcium channel in vitro. Additionally, the phosphorylation of the L-type calcium channel at Ser(1928) induced by isoproterenol was impaired in neonatal Cypher/ZASP-null cardiomyocytes. Moreover, Cypher/ZASP interacted with the Ser/Thr phosphatase calcineurin, which is a phosphatase for the L-type calcium channel. Taken together, our data strongly suggest that Cypher/ZASP not only plays a structural role for the sarcomeric integrity, but is also an important sarcomeric signaling scaffold in regulating the phosphorylation of channels or contractile proteins. |
