Role of Deubiquitinases in CMV Pathogenesis - Project Summary/Abstract
All viruses must navigate the cellular ubiquitin (Ub) system en route to successful infection. Ubiquitin is a versatile
posttranslational modification controlling many diverse cellular processes, from protein quality control, trafficking
and degradation to signal transduction pathways. Activation of sequential E1-E2-E3 Ub-ligase cascades result
in covalent attachment of one or more Ub molecules to lysine residues in substrate proteins. Arrays of different
Ub-Ub linkages, in large part, dictate the regulatory role of Ub modification on the stability, localization, or function
of target proteins. Conversely, Ub can be removed from modified proteins to reverse its effects through the
activities of numerous deubiquitinating enzymes (DUBs). All herpesviruses encode DUBs that are implicated in
facilitating the viral life cycle; however, a thorough understanding of the activity, specificity, and biology of these
viral DUBs during a natural infection remains incomplete. We have previously shown that the conserved DUB
encoded by the murine cytomegalovirus (MCMV) controls inflammation and viral pathogenesis during infection
in a natural host. It does so by regulating the host ER-associated degradation (ERAD) and other pathways, to
control the expression and secretion of a critical viral chemokine. The objective of this research plan is to
determine the molecular mechanisms by which MCMV DUB facilitates pathogenesis during infection in a natural
host. Our preliminary data lead to the overall hypothesis that MCMV DUB activity targets both host and viral
factors to evade innate immune responses and facilitate viral infection. This hypothesis will be tested by pursuing
two specific aims: 1) determine the mechanisms of CMV DUB activity regulating host ERAD and protein
trafficking pathways during infection and 2) determine the linkage specificity target substrates of the MCMV DUB
in vitro and during infection. These efforts will yield significant mechanistic insight into the complex and novel
role CMV deubiquitinases play in pathogenesis and host responses, and underscore the potential utility of
targeting DUB functions to combat viral infections.