| Identification of the cell cycle regulator VCP ( p97 / CDC48 ) as a substrate of the band 4 . 1 related protein tyrosine phosphatase PTPH 1 . ^^^ The PTPH 1 D811A mutant trapped primarily a 97 kDa tyrosine phosphorylated protein , which was determined to be VCP ( also named p 97 or yeast CDC 48 ) , from various cell lysates in vitro . ^^^ Moreover , induction of wild type PTPH 1 resulted in specific dephosphorylation of VCP without changing the overall phosphotyrosine profile of the cells . ^^^ Our results suggest that PTPH 1 may exert its effects on cell growth through dephosphorylation of VCP , thus implicating tyrosine phosphorylation as an important regulator of VCP function . . ^^^ |