Catalytic domain of the Serine/Threonine Kinases, Chlamydomonas reinhardtii FA2 and similar proteins
STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. Chlamydomonas reinhardtii FA2 was discovered in a genetic screen for deflagellation-defective mutants. It is essential for basal-body/centriole-associated microtubule severing, and plays a role in cell cycle progression. No cellular function has yet been ascribed to CNK4. The Chlamydomonas reinhardtii FA2-like subfamily belongs to the (NIMA)-related kinase (Nek) family, which includes seven different Chlamydomonas Neks (CNKs 1-6 and Fa2). This subfamily contains FA2 and CNK4. The Nek family is part of a larger superfamily that includes the catalytic domains of other STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.