Pleckstrin Homology Domain Containing Family A, Member 4 (PLEKHA4)

By searching EST databases for proteins containing a putative phosphatidylinositol 3,4,5-trisphosphate-binding motif (PPBM), followed by screening a human universal cDNA library, Dowler et al. (2000) obtained a full-length cDNA encoding PLEKHA4, which they designated PEPP1. The deduced 779-amino acid protein contains an N-terminal pleckstrin homology (PH) domain. Northern blot analysis did not detect expression in any normal tissue, but a 3-kb transcript was detected at high levels in a melanoma cancer cell line. Dowler et al. (2000) also identified PEPP1 ESTs in melanoma and melanocyte cDNA libraries, suggesting that expression is likely restricted to melanomas and melanocytes.PEPP1 showed significant affinity for phosphatidylinositol 3-phosphate in vitro, but it did not bind to any other phosphoinositide examined.