D1 ring is stable and nucleotide-independent, whereas D2 ring undergoes major conformational changes during the ATPase cycle of p97-VCP

The 97-kDa valosin-containing protein (p97-VCP) belongs to the AAA (ATPases associated with various cellular activities) family and acts as a molecular chaperone in diverse cellular events, including ubiquitinproteasome-mediated degradation. We previously showed that VCP contains a substrate-binding domain, N, and two conserved ATPase domains, D1 and D2, of which D2 is responsible for the major enzyme activity. VCP has a barrel-like structure containing two stacked homo-hexameric rings made of the D1 and D2 domains, and this structure is essential for its biological functions. During ATPase cycles, VCP undergoes conformational changes that presumably apply tensions to the bound substrate, leading to the disassembly of protein complexes or unfolding of the substrate. How ATPase activity is coupled with the conformational changes in VCP complex and the D1 and D2 rings is not clear. In this report, we took biochemical approaches to study the structure of VCP in different nucleotide conditions to depict the conformational changes in the ATPase cycles. In contrast to many AAA chaperones that require ATP/ADP to form oligomers, both wild type VCP and ATP-binding site mutants can form hexamers without the addition of nucleotide. This nucleotide-independent hexamerization requires an intact D1 and the down-stream linker sequence of VCP. Tryptophan fluorescence and trypsin digestion analyses showed that ATP/ADP binding induces dramatic conformational changes in VCP. These changes do not require the presence of an intact ATP-binding site in D1 and is thus mainly attributed to the D2 domain. We propose a model whereby D1, although undergoing minor conformational changes, remains as a relatively trypsin-resistant hexameric ring throughout the ATPase cycle, whereas D2 only does so when it binds to ATP or ADP. After ADP is released at the end of the ATP hydrolysis, D2 ring is destabilized and adopts a relatively flexible and open structure.

Medienart:

Artikel

Erscheinungsjahr:

2003

Erschienen:

2003

Enthalten in:

Zur Gesamtaufnahme - volume:278

Enthalten in:

The Journal of biological chemistry - 278(2003), 35 vom: 29. Aug., Seite 32784-93

Sprache:

Englisch

Beteiligte Personen:

Wang, Qing [VerfasserIn]
Song, Changcheng [VerfasserIn]
Yang, Xiaoyi [VerfasserIn]
Li, Chou-Chi H [VerfasserIn]

Themen:

61D2G4IYVH
8DUH1N11BX
8L70Q75FXE
Adenosine Diphosphate
Adenosine Triphosphatases
Adenosine Triphosphate
Cell Cycle Proteins
EC 3.6.1.-
EC 3.6.4.6
Journal Article
Molecular Chaperones
Nucleotides
Recombinant Fusion Proteins
Research Support, U.S. Gov't, P.H.S.
Tryptophan
Valosin Containing Protein

Anmerkungen:

Date Completed 02.10.2003

Date Revised 08.04.2022

published: Print-Electronic

Citation Status MEDLINE

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM125717318