The multiple functions of protein phosphatase 6

This review presents the accumulating evidence for the roles of protein phosphatase 6 (PP6) in cell cycle, DNA damage repair, inflammatory signaling, lymphocyte development, virus infection, tumor formation/progression, cell/tissue size, and non-coding RNA-mediated regulation. PP6 is an evolutionarily conserved and ubiquitously expressed Ser/Thr protein phosphatase most closely related to protein phosphatase 2A (PP2A) and protein phosphatase 4 (PP4). Although abundantly expressed in cells with multiple roles in cellular signaling, PP6 has received less attention than its close relative PP2A. Many studies used okadaic acid as PP2A inhibitor, even though these toxins also inhibit PP6 activity, so effects of the inhibitor could have been due to inhibition of both phosphatases. PP6 has its own dedicated subunits that assemble into heterotrimers that presumably fulfill its discrete functions in cells.