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Protein kinase C δ signaling at mitochondria revealed by live cell fluorescence imaging, chemical genetics, and biochemical studies
Author(s) -
WuZhang Alyssa Xia,
Kajimoto Taketoshi,
Newton Alexandra C.
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.772.1
Subject(s) - protein kinase c , mitochondrion , microbiology and biotechnology , isozyme , biology , signal transduction , chemistry , biochemistry , enzyme
Mitochondria serve the cell's energy needs and, in response to intracellular signals, execute programmed cell death. Protein kinase C δ (PKCδ), a member of the PKC family of signal transduction isozymes whose dysregulation is implicated in diseases such as cancer and diabetes, has been shown to be essential in mitochondrial‐dependent apoptosis. Here we dissect the molecular mechanisms driving PKCδ interaction with mitochondria. Using FRET‐based imaging, we show that phorbol ester induces acute translocation of PKCδ to mitochondria that is isozyme‐specific, independent of the C2 and C1A domains and of PKC activity, insufficient with the catalytic domain alone, and dependent on the C1B domain. Mitochondrial PKCδ has robust activity at the outer membrane, as revealed by a FRET reporter of PKC activity (CKAR) modified here to report PKCδ activity specifically (δCKAR). Using a PKCδ gate‐keeper mutant with a modified active site, we show that specific inhibition of PKCδ activity neither prevents nor reverses its translocation to mitochondria. Lastly, biochemical studies confirm basal interaction of exogenous PKCδ with and the presence of endogenous PKCδ at mitochondria. These data reveal unique properties of PKCδ that allow isozyme‐specific function at mitochondria. This research was supported by NIH GM43154 (ACN) and NIH Pharmacology Training Grant NIH 2 T32 GM07752 (AXW).