PRM quantification of MCS proteins and viral proteins in HCMV virus microenvironment

The control of host processes which influence cell-cell communication is central to determining the outcome of a virus infection in tissue. Despite this, it remains unclear how cells either in close or distant proximity to an infected cell differentially respond to the primary infection. We established a virus infection microenvironment to resolve molecular features and functional consequences of cell spatial address within this localized niche by proteomic analyses, and identified differential regulations of membrane contact site (MCS) proteins in different cell populations. Here, we conducted targeted mass spectrometry (PRM) analyses for all MCS proteins representing every major organelle-organelle association, and identified elevation of MCS proteins in infected and neighboring cells. To check the contribution of extracellular vesicle (EV) dependent mechanism to the viral proteins detected in the neighboring cells, HCMV protein PRM analyses were conducted with or without EV inhibitors, GW4869 or manumycin A (MA), showing that EVs contribute to the viral protein levels in neighboring population.