Probable cyclin-dependent kinase whose activity is most likely regulated by the cyclin cyl-1/Cylin-L (PubMed:29886128). Acts partially redundantly with cdk-11.1 to ensure embryonic viability (PubMed:29886128). In contrast to cdk-11.1, not essential for male and female fertility (PubMed:29886128). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Evenly distributed between the cytoplasm and nucleus in embryos, but becomes more enriched in the nucleus from the 4- and 6-cell stage as embryos develop (PubMed:29886128). In the germline, localizes to the nucleus and cytoplasm in the mitotic region, but is enriched in the cytoplasm (PubMed:29886128). Nuclear localization increases as cells enter late pachytene, and then the distribution between the cytoplasm and nucleus becomes more even as oocytes mature (PubMed:29886128). Expressed in somatic cells and at varying levels throughout the germline (at protein level) (PubMed:29886128). Highly expressed in the germ line of hermaphrodites (at protein level) (PubMed:29886128). Expression in embryos increases as development proceeds (at protein level). Viable, with no visible phenotype (PubMed:29886128). Knockout combined with RNAi-mediated knockdown of cdk-11.1 at the L1 stage of larval development results in sterility (PubMed:29886128). Knockout combined with RNAi-mediated knockdown of cdk-11.1 at the L4 larval stage results in fertile adults that produce few viable embryos (PubMed:29886128). Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. CDC2/CDKX subfamily.