Proteomic Analysis of PP2A/B56(gamma)1-associated Cardiac Proteins Reveals Phosphorylation-regulated Players in EC Coupling and Heart-failure

摘要

Dysfunction of cardiac excitation-contraction (EC) coupling and changes of gene expression have been linked to many animal models of heart failure and human heart disease. Recent evidence reveals that phosphatases are active modulators that control signaling functions through local targeting to macromolecular complexes in heart cells. The serine/threonine phosphatase type 2A (PP2A), a ubiquitous conserved phosphatase, consists of a common dimeric core comprised of a catalytic C and structural/scaffolding A subunit, associated with a variety of exchangeable targeting or B subunits. One such protein, B56(gamma)1 is highly expressed in hearts and confocal immuno-fluorescence imaging reveal that is localizes to strategic sites in cardiac myocytes, z-lines/t-tubules and nuclear speckles.