FIGURE 10.

Model showing three mechanisms for the agonist-evoked redistribution of cytosolic PKCδ to intracellular compartments and summarizing the determinants involved in its interaction with mitochondria. Arrow 1, canonical binding of PKCδ to DAG-containing membranes such as the plasma membrane (shown) and Golgi is mediated by the C1B domain. Arrow 2, Src-dependent translocation of PKCδ to the nucleus depends on Tyr phosphorylation (indicated by red circles) of PKCδ. Arrow 3, the novel, isozyme-specific interaction of PKCδ with mitochondria occurs via two steps: step A, an initial recruitment step that depends on the C1A and C1B domains and on Leu-Asn (LN) in the turn motif, and step B, a retention step that depends on four elements: the C2 domain, an acidic residue in the activation loop (Glu-500, E500), intrinsic catalytic activity (represented by ATP→ADP), and the mitochondrial membrane potential (represented by plus and minus signs). One or more protein scaffolds (gray rectangles) at mitochondria are hypothesized to mediate this interaction, which promotes mitochondrial respiration.