The molecular chaperone calnexin associates with the vacuolar H+-ATPase from oat seedlings

Xuhang Li, Robert T C Su, Hei Ti Hsu, Heven Sze

Research output: Contribution to journalArticle

Abstract

Acidification of endomembrane compartments by the vacuolar-type H+-ATPase (V-ATPase) is central to many cellular processes in eukaryotes, including osmoregulation and protein sorting. The V-ATPase complex consists of a peripheral sector (V1) and a membrane integral sector (V(o)); however, it is unclear how the multimeric enzyme is assembled. A 64-kD polypeptide that had copurified with oat V-ATPase subunits has been identified as calnexin, an integral protein on the endoplasmic reticulum. To determine whether calnexin interacted physically with the V-ATPase, microsomal membranes were Triton X-100 solubilized, and the protein-protein interaction was analyzed by coimmunoprecipitation. Monoclonal antibodies against calnexin precipitated both calnexin and V-ATPase subunits, including A and B and those of 44, 42, 36, 16, and 13 kD. A monoclonal antibody against subunit A precipitated the entire V-ATPase complex as well as calnexin and BiP, an endoplasmic reticulum lumen chaperone. The results support our hypothesis that both calnexin and BiP act as molecular chaperones in the folding and assembly of newly synthesized V1V(o)-ATPases at the endoplasmic reticulum.

Original languageEnglish (US)
Pages (from-to)119-130
Number of pages12
JournalPlant Cell
Volume10
Issue number1
DOIs
StatePublished - Jan 1998
Externally publishedYes

Fingerprint

calnexin
Calnexin
Vacuolar Proton-Translocating ATPases
molecular chaperones
H-transporting ATP synthase
Molecular Chaperones
Seedlings
oats
seedlings
Endoplasmic Reticulum
endoplasmic reticulum
Proton-Translocating ATPases
monoclonal antibodies
Proteins
Monoclonal Antibodies
Membranes
Osmoregulation
protein transport
Acidification
osmoregulation

ASJC Scopus subject areas

  • Plant Science
  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Cell Biology

Cite this

The molecular chaperone calnexin associates with the vacuolar H+-ATPase from oat seedlings. / Li, Xuhang; Su, Robert T C; Hsu, Hei Ti; Sze, Heven.

In: Plant Cell, Vol. 10, No. 1, 01.1998, p. 119-130.

Research output: Contribution to journalArticle

Li, Xuhang ; Su, Robert T C ; Hsu, Hei Ti ; Sze, Heven. / The molecular chaperone calnexin associates with the vacuolar H+-ATPase from oat seedlings. In: Plant Cell. 1998 ; Vol. 10, No. 1. pp. 119-130.
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