The function of MVP (major vault protein, ENSG00000013364) is as follows. Structural component of the vault particle, which is a massive ribonucleoprotein complex that may play a role in cargo transport and signal transduction (PubMed:40691181). Oligomerizes to form a cage-like vault complex, which can house several minor vault components including PARP4 (PubMed:40691181). Vaults may play a role in nucleo-cytoplasmic transport (PubMed:15133037). Down-regulates IFNG- mediated STAT1 signaling and subsequent activation of JAK (PubMed:16418217). Down-regulates SRC activity and signaling through MAP kinases (PubMed:16441665). {ECO:0000269|PubMed:15133037, ECO:0000269|PubMed:16418217, ECO:0000269|PubMed:16441665, ECO:0000269|PubMed:40691181}.