Functions redudantly with AGC1-7 as signaling component in the pollen tube. Required for polarized growth of pollen tubes. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Activated by PDPK1/PDK1. Interacts with PDPK1/PDK1. Specifically expressed in pollen grains. Autophosphorylated and phosphorylated by PDPK1/PDK1. No visible phenotype under normal growth conditions, but pollen of the double mutants agc1.5 and agc1.7 is impaired in polarized growth of pollen tube. Belongs to the protein kinase superfamily. AGC Ser/Thr protein kinase family.