Vaults: a ribonucleoprotein particle involved in drug resistance?
Vaults are ribonucleoprotein particles found in the cytoplasm of eucaryotic cells. The 13 MDa particles are composed of multiple copies of three proteins: an M(r) 100 000 major vault protein (MVP) and two minor vault proteins of M(r) 193 000 (vault poly-(ADP-ribose) polymerase) and M(r) 240 000 (telomerase-associated protein 1), as well as small untranslated RNA molecules of approximately 100 bases. Although the existence of vaults was first reported in the mid-1980s no function has yet been attributed to this organelle. The notion that vaults might play a role in drug resistance was suggested by the molecular identification of the lung resistance-related (LRP) protein as the human MVP. MVP/LRP was found to be overexpressed in many chemoresistant cancer cell lines and primary tumor samples of different histogenetic origin. Several, but not all, clinico-pathological studies showed that MVP expression at diagnosis was an independent adverse prognostic factor for response to chemotherapy. The hollow barrel-shaped structure of the vault complex and its subcellular localization indicate a function in intracellular transport. It was therefore postulated that vaults contributed to drug resistance by transporting drugs away from their intracellular targets and/or the sequestration of drugs. Here, we review the current knowledge on the vault complex and critically discuss the evidence that links vaults to drug resistance.
Mossink
Marieke H
MH
Department of Hematology, Erasmus Medical Center, PO Box 1738, 3000 DR Rotterdam, The Netherlands.
van Zon
Arend
A
Scheper
Rik J
RJ
Sonneveld
Pieter
P
Wiemer
Erik A C
EA
D000818:Animals; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D006801:Humans; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology; D020394:Vault Ribonucleoprotein Particles / Q000737:chemistry / Q000378:metabolism*; D000099187:Major Vault Protein
D020394:Vault Ribonucleoprotein Particles; D000099187:Major Vault Protein