Protein kinase that recognizes phosphorylation sites in which the surrounding peptides have an alpha-helical conformation (By similarity). Regulates cardiac development and cardiomyocyte differentiation by negatively regulating Wnt/beta-catenin signaling (PubMed:29888752). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Expressed in developing cardiac tissue. Detected at 13 hours post-fertilization (hpf) in the precursor cells of adaxial cells (slow twitch muscle fibers) of the paraxial mesoderm (PubMed:29888752). At 22 hpf, detected in the developing heart (PubMed:29888752). Morpholino knockdown in the embryo causes reduced heart beating rates and cardiomyocyte numbers at 48 hours post-fertilization (hpf) (PubMed:29888752). At 72 hpf, embryos display pericardial and yolk sac effusion and pronounced cardiac malformation coupled with defects in posterior development (PubMed:29888752). Embryos also lack ventricular epicardium at 96 hpf (PubMed:29888752). Belongs to the protein kinase superfamily. Alpha-type protein kinase family. ALPK subfamily.