© 2006 The Japanese Biochemical Society.
Regular Paper |
Saccharomyces cerevisiae Rot1p Is an ER-Localized Membrane Protein That May Function with BiP/Kar2p in Protein Folding
1 Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama, Ikoma, Nara 630-0192; and 2 Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba 277-8562
To whom correspondence should be addressed. Tel: +81-743-72-5640, Fax: +81-743-72-5649, E-mail: kkouno{at}bs.naist.jp
The 70-kDa heat shock protein (Hsp70) family of molecular chaperones cooperates with cofactors to promote protein folding, assembly of protein complexes and translocation of proteins across membranes. Although many cofactors of cytosolic Hsp70s have been identified, knowledge about cofactors of BiP/Kar2p, an endoplasmic reticulum (ER)–resident Hsp70, is still poor. Here we propose the Saccharomyces cerevisiae protein Rot1p as a possible cofactor of BiP/Kar2p involved in protein folding. Rot1p was found to be an essential, ER-localized membrane protein facing the lumen. ROT1 genetically interacted with several ER chaperone genes including KAR2, and the rot1-2 mutation triggered the unfolded protein response. Rot1p associated with Kar2p, especially under conditions of ER stress, and maturation of a model protein, a reduced form of carboxypeptidaseY, was impaired in a kar2-1 rot1-2 double mutant. These findings suggest that Rot1p participates in protein folding with Kar2p. Morphological analysis of rot1-2 cells revealed cell wall defects and accumulation of autophagic bodies in the vacuole. This implies that the protein folding machinery in which Rot1p is involved chaperones proteins acting in various physiological processes including cell wall synthesis and lysis of autophagic bodies.
* Present address: Department of pathology, University of Florida College of Medicine, Gainesville, FL 32610-0275, USA.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  M. Takeuchi, Y. Kimata, and K. Kohno Saccharomyces cerevisiae Rot1 Is an Essential Molecular Chaperone in the Endoplasmic Reticulum Mol. Biol. Cell, August 1, 2008; 19(8): 3514 - 3525. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Nakamata, T. Kurita, M. S. A. Bhuiyan, K. Sato, Y. Noda, and K. Yoda KEG1/YFR042w Encodes a Novel Kre6-binding Endoplasmic Reticulum Membrane Protein Responsible for beta-1,6-Glucan Synthesis in Saccharomyces cerevisiae J. Biol. Chem., November 23, 2007; 282(47): 34315 - 34324. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. A. Juanes, E. Queralt, M. C. Bano, and J. C. Igual Rot1 plays an antagonistic role to Clb2 in actin cytoskeleton dynamics throughout the cell cycle J. Cell Sci., July 15, 2007; 120(14): 2390 - 2401. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Oikawa, Y. Kimata, and K. Kohno Self-association and BiP dissociation are not sufficient for activation of the ER stress sensor Ire1 J. Cell Sci., May 1, 2007; 120(9): 1681 - 1688. [Abstract] [Full Text] [PDF]
|
|