Plays a role in transformation by modulating the activities of cellular proteins involved in control of cell proliferation and by acting as a functional homolog of an activated tyrosine kinase-associated growth-factor receptor. Recruits upon association with Ppp2/PP2A the Src tyrosine kinase component Fyn, thereby activating its kinase activity. In turn, MT becomes phosphorylated and mediates signal transduction pathways leading to cell cycle progression and cell division. MT also plays a role in regulation of early and late gene expression as well as viral DNA replication (By similarity). Interacts with host Ppp2/PP2A A and C subunits; this interaction alters PP2A substrate specificity and localization (By similarity). Interacts with host Fyn.