Protein Kinase D3 (PRKD3), also known as Protein Kinase C nu (PKC nu), is a member of the Protein Kinase D (PKD) protein family. PRKD3/PKC nu is an 890 amino acid (aa) protein with a predicted molecular mass of 100 kDa. The rodent PRKD3/PKC nu orthologs share 96% aa sequence identity with the human protein. Two alternatively spliced isoforms of PRKD3/PKC nu have been identified in humans. PRKD3/PKC nu is a diacylglycerol receptor and a direct substrate of PKC epsilon and PKC eta. It is ubiquitously expressed and present in the cytoplasm, but translocation to the plasma membrane is required for its activation. PRKD3/PKC nu is implicated in intracellular signaling pathways that promote cell proliferation, differentiation, transformation, motility, protein transport, membrane trafficking, cell survival, and apoptosis. It is also implicated in B cell receptor and T cell receptor signaling.