Has a role in establishing the characteristic rod cell shape. Important for cell polarity and is involved in directing growth to the cell ends. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Localized to the cell tips except during mitosis. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.