Has no detectable ceramide-kinase activity. Overexpression of CERKL protects cells from apoptosis in oxidative stress conditions. Enriched in nucleoli. May shuttle between nucleus and cytoplasm. Isoform 5 is not enriched in the nucleoli. Isoform 1 and isoform 2 are expressed in adult retina, liver and pancreas as well as in fetal brain, lung and kidney. Isoform 3 is expressed in adult retina as well as in fetal lung and liver. Isoform 4 is expressed in adult retina, lung and kidney as well as in fetal lung and liver. Moderately expressed in retina, kidney, lung, testis, trachea, and pancreas. Weakly expressed in brain, placenta and liver. Expressed in fetal lung, kidney and brain. Phosphorylated on serine residues. The disease is caused by variants affecting the gene represented in this entry. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay. Wrong choice of CDS.