Distinct Roles for the AAA ATPases NSF and p97 in the Secretory Pathway
AUTOR(ES)
Dalal, Seema
FONTE
The American Society for Cell Biology
RESUMO
NSF and p97 are related AAA proteins implicated in membrane trafficking and organelle biogenesis. p97 is also involved in pathways that lead to ubiquitin-dependent proteolysis, including ER-associated degradation (ERAD). In this study, we have used dominant interfering ATP-hydrolysis deficient mutants (NSF(E329Q) and p97(E578Q)) to compare the function of these AAA proteins in the secretory pathway of mammalian cells. Expressing NSF(E329Q) promotes disassembly of Golgi stacks into dispersed vesicular structures. It also rapidly inhibits glycosaminoglycan sulfation, reflecting disruption of intra-Golgi transport. In contrast, expressing p97(E578Q) does not affect Golgi structure or function; glycosaminoglycans are normally sulfated and secreted, as is the VSV-G ts045 protein. Instead, expression of p97(E578Q) causes ubiquitinated proteins to accumulate on ER membranes and slows degradation of the ERAD substrate cystic-fibrosis transmembrane-conductance regulator. In addition, expression of p97(E578Q) eventually causes the ER to swell. More specific assessment of effects of p97(E578Q) on organelle assembly shows that the Golgi apparatus disperses and reassembles normally after treatment with brefeldin A and during mitosis. These findings demonstrate that ATP-hydrolysis-dependent activities of NSF and p97 in the cell are not equivalent and suggest that only NSF is directly involved in regulating membrane fusion.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=329284Documentos Relacionados
- Structure, dynamics and interactions of p47, a major adaptor of the AAA ATPase, p97
- Recombinant vaccinia virus vaccine against the human melanoma antigen p97 for use in immunotherapy.
- Role of p97 and Syntaxin 5 in the Assembly of Transitional Endoplasmic Reticulum
- Functional domains in nuclear import factor p97 for binding the nuclear localization sequence receptor and the nuclear pore.
- Quantitative analysis of melanoma-associated antigen p97 in normal and neoplastic tissues.