Analysis of the expression, localization and activity of rat casein kinase 1epsilon-3.

Casein kinase 1epsilon (CK1epsilon) is a serine/threonine protein kinase that has been suggested to participate in the regulation of various signaling pathways. In this report, we examined the tissue distributions of three putative alternatively spliced forms of rCk1epsilon by RT-PCR. This analysis confirmed that all three isoforms are expressed in rat tissues with different tissue-specific expression patterns. Immunohistochemical analysis showed that the intracellular distribution of rCK1epsilon-3 in neurons was broader than that of rCK1epsilon-1. Moreover, the kinase activity of the rCK1epsilon-3 protein differed from that of rCK1epsilon-1. These data suggest that rCK1epsilon-1 and rCK1epsilon-3 may play different functional roles.