| The human tumor suppressor arf interacts with spinophilin / neurabin 2 , a type 1 protein phosphatase binding protein . ^^^ We report here that the human homologue of spinophilin / neurabin 2 , a regulatory subunit of protein phosphatase 1 catalytic subunit specifically interacts with ARF , both in yeast and in mammalian cells . ^^^ We also show that ectopic expression of spinophilin / neurabin 2 inhibits the formation of G 418 resistant colonies when transfected into human and mouse cell lines , regardless of p 53 and ARF status . ^^^ Moreover , spinophilin / ARF coexpression in Saos 2 cells , where ARF ectopic expression is ineffective , somehow results in a synergic effect . ^^^ These data demonstrate a role for spinophilin in cell growth and suggest that ARF and spinophilin could act in partially overlapping pathways . . ^^^ |