Phosphorylase b kinase catalyzes the phosphorylation of serine in certain substrates, including troponin I. The alpha chain may bind calmodulin. By phosphorylation of various serine residues and by calcium. Glycan biosynthesis; glycogen metabolism. Hexadecamer of 4 heterotetramers, each composed of alpha, beta, gamma, and delta subunits. Alpha (PHKA1 or PHKA2) and beta (PHKB) are regulatory subunits, gamma (PHKG1 or PHKG2) is the catalytic subunit, and delta is calmodulin. Predominantly expressed in liver and other non-muscle tissues. Although the final Cys may be farnesylated, the terminal tripeptide is probably not removed, and the C-terminus is not methylated. The disease is caused by variants affecting the gene represented in this entry. Belongs to the phosphorylase b kinase regulatory chain family.