Meta-Biol

• Pathways

Protein kinase C-delta (PRKCD), activated upon CLEC7A (Dectin-1)-SYK signaling, phosphorylates CARD9 leading to NF-kB activation (Strasser et al. 2012) and complex formation between CARD9 and BCL10. CLEC6A (Dectin-2) and CLEC4E (Mincle) also induces intracellular signaling through PRKCD and CARD9-BCL10-MALT1 pathway. Similar to the CLEC7A responses, both CLEC6A and CLEC4E-induced interleukin 10 (IL10) and tumour necrotic factor (TNF) production were severely impaired in the absence of PRKCD (Strasser et al. 2012). PRKCD is a member of the Ca2+ independent and diacylglycerol (DAG) dependent novel PKC subfamily. PKC family members exist in an immature inactive conformation that requires post-translational modifications to achieve catalytic maturity. The catalytic maturation of PRKCD involves the auto-phosphorylation of Ser645 and the phosphorylation of Thr507 and Ser664 (Li et al. 1997, Keranen et al. 1995). These phosphorylations of activation loop residues act as a priming step that allows the catalytic maturation of PRKCD (Dutil et al. 1998). Fully phosphorylated and primed PRKCD localises to the cytosol with its pseudosubstrate occupying the substrate-binding cavity. Signals that cause the lipid hydrolysis recruit PKC to membranes. The C1 domain in PRKCD is a cysteine-rich compact structure, identified as the interaction site for DAG and phorbol ester. PRKCD preferentially translocates to the plasma membrane (Stahelin et al. 2004, Newton 2010).