text: Through the process of alternative splicing, the CKLF gene encodes 4 CKLF protein isoforms, i.e. proteins made from different areas of the same gene. These isoforms are 1) CKLF1 and CKLF3 proteins that consist  of 99 and 67 amino acids, respectively, and are secreted from their parent cells and 2) CKLF2 (which is the full-length product of the CKLF gene) and CKLF4 proteins which consist of 152 and 120 amino acids, respectively, and are located in the membranes of their parent cells.