Mitochondrial PKC epsilon in cardiac protection

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DESCRIPTION (provided by applicant): Nitric oxide (NO) donors protect against myocardial ischemia/reperfusion injury via signaling mechanisms that involve protein kinase C e (PKCe). The downstream effectors targeted by PKCe to carry out protection remain poorly defined. A recent study has implicated the adenine nucleotide translocator (ANT1)---a core unit of the mitochondrial permeability transition (MPT) pore as a signaling partner of PKC(. The focus of the current investigation is to determine whether NO donors, clinically relevant cardiac protective drugs, act via modulation of the ANT1 component of the MPT pore and to examine the role of direct modification of the pore by PKCe in this process. The study will employ standard mitochondrial function assays, to measure MPT pore activity, standard biochemistry procedures, to determine protein expression and interactions, and state-of-the-art mass spectrometry, to examine phosphorylation of ANT1 by PKC(. The central hypothesis is that a critical task of PKCe in NO donor-induced cardiac protection is to reduce the propensity for mitochondrial permeability transition. This action involves, in part, direct modification of a core component of the MPT pore, ANT1. The specific aims are: (1) To elucidate the role of PKCe-dependent regulation of mitochondrial permeability transition in a murine model of NO-induced cardiac protection. (2) To determine whether ANT1, an essential element of the MPT pore, is a downstream molecular target of PKC( and to identify the specific amino acid residues of ANT1 phosphorylated by PKCe during NO-induced cardiac protection.