Required for normal vault structure. Vaults are multi-subunit structures that may act as scaffolds for proteins involved in signal transduction. Vaults may also play a role in nucleo-cytoplasmic transport. Down-regulates IFNG-mediated STAT1 signaling and subsequent activation of JAK. Down-regulates SRC activity and signaling through MAP kinases (By similarity). The vault ribonucleoprotein particle is a huge (400 A x 670 A) cage structure of 12.9 MDa. It consists of a dimer of half-vaults, with each half-vault comprising 39 identical major vault protein (MVP) chains, PARP4 and one or more vault RNAs (vRNAs). Interacts with TEP1. Interacts with PTEN and activated MAPK1. The phosphorylated protein interacts with the SH2 domains of PTPN11 and SRC. Interacts with APEX1 (By similarity). May interact with ZNF540 (By similarity). MVP 3 mediates interaction with PTEN. MVP 4 mediates interaction with PARP4. Phosphorylated on Tyr residues after EGF stimulation. Dephosphorylated by PTPN11.