Receptor-like kinase involved in the control of pollen germination and pollen tube polar growth (PubMed:23024212). Can phosphorylate ROPGEF1 in vitro (PubMed:23024212). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] The phosphorylation activity is calcium-independent. Interacts in vitro with ROPGEF1 (via PRONE domain) (PubMed:23024212). Interacts with PRK6 (PubMed:26961657). Expressed in pollen and/or in flowers, but not in leaves. The protein kinase domain may be catalytically impaired due to the lack of the conserved Asp active site at position 486, which is replaced by a Asn residue. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.