title: Cellular serine/threonine phosphatase activity during human cytomegalovirus infection.
abstract: While the importance of cellular and viral kinases in HCMV replication has been demonstrated, relatively little is known about the activity of cellular phosphatases. We conducted a series of experiments designed to investigate the effect of HCMV infection on cellular serine/threonine phosphatase activity. We found that the abundance of two major cellular serine/threonine phosphatases, PP1 and PP2A, increases during HCMV infection. This was associated with an increase in threonine phosphatase activity in HCMV-infected cells. HCMV infection conferred resistance to the effects of the phosphatase inhibitors calyculin A (CA) and okadaic acid with regards to global protein hyperphosphorylation and the shutoff of protein synthesis. The protective effect of HCMV infection could be overcome at a high concentration of CA, suggesting that cellular phosphatase activity is required for critical cellular processes during HCMV infection. Specifically, phosphatase activity was required to limit the accumulation of phospho-eIF2alpha, but not phospho-PKR, during HCMV infection.
authors.affiliation: Divisions of Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA. mhakki@fhcrc.org
authors.forename: Morgan
authors.initials: M
authors.lastname: Hakki
authors.forename: Adam P
authors.initials: AP
authors.lastname: Geballe