PCNA Associated Factor 15kDa (PAF)

p15(PAF) bound endogenous PCNA in human embryonic kidney 293 cells, and mutation analysis indicated that ile65 and phe68 of p15(PAF) were required for the interaction. Overexpressed p15(PAF) competed with p21(WAF1) (CDKN1A) for PCNA binding in 293 cells. Expression of p15(PAF) was significantly increased in several types of tumor tissues, particularly in esophageal tumors. The deduced protein contains 111 amino acids. Northern blot analysis detected high expression in thymus and colon, intermediate expression in placenta, liver, kidney, spleen, ovary, small intestine, and peripheral blood leukocytes, weak expression in lung, pancreas, and testis, and no expression in heart, brain, skeletal muscle, and prostate. Expression was also detected in HeLa cells.