Arsenite Inducible RNA Associated Protein (AIRAP)

Airap formed insoluble complexes in arsenite-treated mouse fibroblasts. RNA interference-mediated knockdown of Airap in C. elegans lowered resistance to arsenite, but did not affect viability under standard growth conditions.The deduced 171-amino acid protein contains 2 cysteine- and histidine-rich repeats. Immunohistochemical analysis detected AIRAP in both nuclei and cytoplasm of arsenite-treated mouse fibroblasts, Chinese hamster ovary cells, and HeLa cells. Western blot analysis detected a 19-kD Airap protein in mouse fibroblasts.Airap associated tightly with the 19S cap of the proteasome, altering its biochemical properties to facilitate substrate transit through the particle. Airap knockout in mouse cells or C. elegans resulted in accumulation of polyubiquitinated proteins.