MCV sT interacts with FBW7. (A) Validation of MCV sT and FBW7 interaction. To confirm the interaction of HA-FBW7 and MCV sT LSD domain, a PLA-flow cytometric analysis was carried out in HEK293 cells. Wild-type MCV sT displayed an interaction with FBW7 comparative to the positive control interaction of c-Myc with FBW7, while mutation of sT LSD greatly ablated sT interaction with FBW7, consistent with the finding from previous reports (8, 11). Primary antibodies were utilized at optimized concentrations with HA-tag (C29F4) (1:500), c-Myc (9E10) (1:500), and 2T2 (1:500). (B) Calculated fold difference of mean fluorescence intensity of PLA analyzed by FlowJo software. (C) Protein expression was evaluated by immunoblot analysis.