RAB Like Protein 1 (RBEL1)

Using the p19(Arf) isoform of mouse Cdkn2a as bait in a yeast 2-hybrid screen of a mouse embryonic fibroblast cDNA library, followed by RT-PCR of human brain cDNA, Tompkins et al. (2006) cloned mouse and human PARF. The deduced 729-amino acid human protein has an N-terminal GTP-binding domain, followed by a RAB-like domain, 2 proline-rich sequences, and a C-terminal nuclear localization signal. Using in vitro and in vivo binding assays, including reciprocal immunoprecipitation assays, Tompkins et al. (2006) confirmed that PARF bound p19(ARF), but not the p16(INK4A) isoform of CDKN2A. PARF appeared to shuttle in and out of the nucleus of transfected human cells. Knockdown of PARF by RNA interference enhanced the rate of cell proliferation and reduced the growth inhibitory activity of p19(ARF).