CDC Like Kinase 3 (CLK3)

The CLK3 gene encodes a serine/threonine type protein kinase with a non-conserved N-terminal domain. A long and short isoform (phclk3 and pclk3/152) result from alternative splicing and coexist in different tissues. Isoform phclk3/152 lacks the kinase domain.The longer CLK3 cDNA encodes a predicted 490-amino acid protein that has a nonconserved N-terminal domain, a highly conserved C-terminal kinase domain, and multiple potential phosphorylation sites. This CLK3 isoform has 61% and 51% sequence identity with the CLK2 and CLK1 (CLK) proteins, respectively. The shorter cDNA contains an internal deletion of 97 bp, resulting in a predicted 152-amino acid protein that lacks the kinase domain. Southern blot analysis of human genomic DNA suggested that CLK3 is a single-copy gene.