Serine/threonine-protein kinase which is part sphingolipid-mediated signaling pathway that is required for the internalization step of endocytosis by regulating eisosome assembly and organization, and modulating the organization of the plasma membrane. Phosphorylates and activates PKC1. Activates YPK1 and YPK2, 2 components of signaling cascade required for maintenance of cell wall integrity. Required for stress-induced P-body assembly and regulates global mRNA decay at the deadenylation step. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Sphingoid base activates kinase activity. Localizes at eisosomes, large, immobile complexes that mark sites of endocytosis near the plasma membrane. The PIF-pocket is a small lobe in the catalytic domain required by the enzyme for the binding to the hydrophobic motif of its substrates. It is an allosteric regulatory site that can accommodate small compounds acting as allosteric inhibitors. Long-term depletion of PKH2 in a PKH1 null mutant (Pkh depletion) induces programmed cell death. This is mediated by the lack of Pkh-dependent activation of the PKC1 downstream signaling cascade and results in accumulation of reactive oxigen species (ROS) and DNA fragmentation. Belongs to the protein kinase superfamily. AGC Ser/Thr protein kinase family. PDPK1 subfamily.