title: Activation of brain protein phosphatase-1(I) following cardiac arrest and resuscitation involving an interaction with 14-3-3 gamma.
abstract: The intracellular signaling mechanisms that couple transient cerebral ischemia to cell death and neuroprotective mechanisms provide potential therapeutic targets for cardiac arrest. Protein phosphatase (PP)-1 is a major serine/threonine phosphatase that interacts with and dephosphorylates critical regulators of energy metabolism, ionic balance, and apoptosis. We report here that PP-1(I), a major regulated form of PP-1, is activated in brain by approximately twofold in vivo following cardiac arrest and resuscitation in a clinically relevant pig model of transient global cerebral ischemia and reperfusion. PP-1(I) purified to near homogeneity from either control or ischemic pig brain consisted of the PP-1 catalytic subunit, the inhibitor-2 regulatory subunit, as well as the novel constituents 14-3-3gamma, Rab GDP dissociation protein beta, PFTAIRE kinase, and C-TAK1 kinase. PP-1(I) purified from ischemic brain contained significantly less 14-3-3gamma than PP-1(I) purified from control brain, and purified 14-3-3gamma directly inhibited the catalytic subunit of PP-1 and reconstituted PP-1(I). These findings suggest that activation of brain PP-1(I) following global cerebral ischemia in vivo involves dissociation of 14-3-3gamma, a novel inhibitory modulator of PP-1(I). This identifies modulation of PP-1(I) by 14-3-3 in global cerebral ischemia as a potential signaling mechanism-based approach to neuroprotection.
authors.affiliation: Institute for Neuronal Cell Signaling, Weill Cornell Medical College, Department of Anesthesiology, New York, New York, USA.
authors.forename: Jimcy
authors.initials: J
authors.lastname: Platholi
authors.forename: Paul M
authors.initials: PM
authors.lastname: Heerdt
authors.forename: H Y
authors.initials: HY
authors.lastname: Lim Tung
authors.forename: Hugh C
authors.initials: HC
authors.lastname: Hemmings
mesh_terms: D048948:14-3-3 Proteins / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism*; D004789:Enzyme Activation / Q000502:physiology; D005260:Female; D006323:Heart Arrest / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D054645:Protein Phosphatase 1 / Q000378:metabolism*; D012151:Resuscitation; D015398:Signal Transduction / Q000502:physiology; D013552:Swine
chemical_list: D048948:14-3-3 Proteins; D054645:Protein Phosphatase 1