26,674 bp 13 exons.

3,076 bps.

828 amino acids.

PPP1R13L was originally named RAI, an acronym for RelA associated inhibitor. It was originally identified by yeast two-hybrid screening using RelA as bait. PPP1R13L was shown to associate specifically with relA and inhibit relA mediated NF-kappaB activated transcription when NF-kappaB specific transcription was activated by TNF. Yang et al. found no interaction with p53. The mRNA expression was examined in several tissues and was found to be high in heart, placenta, prostate tissues and detectable in lung, kidney, pancreas, spleen thymus, ovary, small intestine and colon. Bergamaschi et al found that PPP1R13L interacts with p53. Antisense RNA or RNAi mediated down regulation of PPP1R13L expression and induced apoptosis. Increased expression of PPP1R13L lead to increased resistance towards cisplatin and UV-induced apoptosis. This indicates that RAI inhibits apoptosis.
Several studies provide evidence that PPP1R13L expression is increased in tumor tissue. In a study of colorectal adenomas and colorectal cancers, PPP1R13L expression was found to be substantially higher in lesions than in the normal tissue from the same patient. PPP1R13L expression has also been found to be increased in breast carcinomas and in blood cells in patients with acute leukemia.
In a prospective study of lung cancer among 265 lung cancer cases and 272 controls nested within the population based Diet, Cancer and Health study, PPP1R13L expression in mononuclear blood cells (isolated by buffy coat) was not associated with risk of lung cancer. mRNA levels were found to be 41% higher in women than in men.

Genetic Epidemiology:
The most frequently studied polymorphism in PPP1R13L is PPP1R13L IVS1 A4364G (rs1970764). Carriers of the variant allele have been shown to be at decreased risk of basal cell carcinoma among younger persons (< 50 years), breast cancer (60 years).
These results indicate that the haplotype may be associated with risk of cancer primarily among young and middle aged persons and that it may be specific for women.