title: Cypher/ZASP is a novel A-kinase anchoring protein.
abstract: 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 RIIα 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.
authors.affiliation: From the Department of Pathology and Pathophysiology, Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou 310058, China.
authors.forename: Changsong
authors.initials: C
authors.lastname: Lin
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Guo
authors.forename: Stephan
authors.initials: S
authors.lastname: Lange
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Kunfu
authors.initials: K
authors.lastname: Ouyang
authors.forename: Xiang
authors.initials: X
authors.lastname: Yin
authors.forename: Liujun
authors.initials: L
authors.lastname: Jiang
authors.forename: Yibo
authors.initials: Y
authors.lastname: Cai
authors.forename: Yongxin
authors.initials: Y
authors.lastname: Mu
authors.forename: Farah
authors.initials: F
authors.lastname: Sheikh
authors.forename: Sheng
authors.initials: S
authors.lastname: Ye
authors.forename: Ju
authors.initials: J
authors.lastname: Chen
authors.forename: Yuehai
authors.initials: Y
authors.lastname: Ke
authors.forename: Hongqiang
authors.initials: H
authors.lastname: Cheng
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D020746:Calcium Channels, L-Type / Q000378:metabolism*; D002478:Cells, Cultured; D054754:Cyclic AMP-Dependent Protein Kinase RIIalpha Subunit / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D015151:Immunoblotting; D060588:LIM Domain Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D008958:Models, Molecular; D009154:Mutation; D009206:Myocardium / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism; D054731:PDZ Domains / Q000235:genetics; D010766:Phosphorylation; D011485:Protein Binding; D051381:Rats; D012518:Sarcomeres / Q000378:metabolism; D012694:Serine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D020746:Calcium Channels, L-Type; D054754:Cyclic AMP-Dependent Protein Kinase RIIalpha Subunit; D060588:LIM Domain Proteins; C485639:Ldb3 protein, mouse; D012694:Serine
keywords: Akap; Calcineurin; Calcium Channels; Cypher/ZASP; Phosphorylation; Protein Kinase A (PKA)