Novel Kinases Which Phosphorylate Proteins and Proteoglycans in the Secretory Pathway

Protein phosphorylation is a fundamental mechanism regulating nearly every aspect of life. Several secreted proteins are phosphorylated, but the kinases responsible are unknown. We identified a family of atypical protein kinases which have N-terminal signal sequence and localize to the lumen of the endoplasmic reticulum and the Golgi apparatus. One of these kinases known as Fam20C is the Golgi casein kinase and it phosphorylates secretory...