Journal
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Volume 346, Issue 3, Pages 700-706Publisher
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.bbrc.2006.05.182
Keywords
phosphatase inhibitor-1; phosphatases; calcineurin; cyclosporine A; okadaic acid; phospholamban
Categories
Ask authors/readers for more resources
Inhibitor 1 (I-1) is a protein inhibitor of protein phosphatase 1 (PP1), the predominating Ser/Thr phosphatase in the heart. Non-phosphorylated I-1 is inactive, whereas I-1 phosphorylated by protein kinase A (PKA) at Thr35 is a potent PP1 inhibitor. The phosphatases that dephosphorylate I-1Thr35 and thus deactivate I-1 in the heart are not established. Here we overexpressed I-1 in neonatal rat cardiac myocytes with recombinant adenovirus and determined phosphorylation of I-1, and one of the major target proteins of PKA/PP1 in the heart, phospholamban (PLB), by Western blot with phospho-specific antibodies. Incubation with the calcineurin inhibitor cyclosporine A or okadaic acid, used at a concentration preferentially inhibiting phosphatase 2A (PP2A), increased significantly I-1Thr35 (similar to 2- to 6-fold) and PLB Ser16 phosphorylation (similar to 2-fold). The results indicate that calcineurin and PP2A act to maintain a low basal level of phosphorylated (active) I-1 in living cardiac myocytes. Calcineurin may constitute a cross-talk between calcium- and cAMP-dependent pathways. (c) 2006 Elsevier Inc. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available