MCB
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Feng, Y.
Right arrow Articles by Davis, N. G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Feng, Y.
Right arrow Articles by Davis, N. G.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, July 2000, p. 5350-5359, Vol. 20, No. 14
0270-7306/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.

Akr1p and the Type I Casein Kinases Act prior to the Ubiquitination Step of Yeast Endocytosis: Akr1p Is Required for Kinase Localization to the Plasma Membrane

Ying Feng1 and Nicholas G. Davis2,*

Department of Pharmacology1 and Departments of Surgery and Pharmacology,2 Wayne State University School of Medicine, Detroit, Michigan 48201

Received 22 November 1999/Returned for modification 30 December 1999/Accepted 17 April 2000

Ubiquitination of the plasma membrane-localized yeast a-factor receptor (Ste3p) triggers a rapid, ligand-independent endocytosis leading to its vacuolar degradation. This report identifies two mutants that block uptake by blocking ubiquitination, these being mutant either for the ankyrin repeat protein Akr1p or for the redundant type I casein kinases Yck1p and Yck2p. While no obvious defect was seen for wild-type Ste3p phosphorylation in akr1 or yck mutant backgrounds, examination of the Delta 320-413 Ste3p deletion mutant phosphorylation did reveal a clear defect in both mutants. The Delta 320-413 deletion removes 18 Ser-Thr residues (possible YCK-independent phosphorylation sites) yet retains the 15 Ser-Thr residues of the Ste3p PEST-like ubiquitination-endocytosis signal. Two other phenotypes link akr1 and yck mutants: both are defective in phosphorylation of wild-type alpha -factor receptor, and while both are defective for Ste3p constitutive internalization, both remain partially competent for the Ste3p ligand-dependent uptake mode. Yck1p-Yck2p may be the function responsible in phosphorylation of the PEST-like ubiquitination-endocytosis signal. Akr1p appears to function in localizing Yck1p-Yck2p to the plasma membrane, a localization that depends on prenylation of C-terminal dicysteinyl motifs. In akr1Delta cells, Yck2p is mislocalized, showing a diffuse cytoplasmic localization identical to that seen for a Yck2p mutant that lacks the C-terminal Cys-Cys, indicating a likely Akr1p requirement for the lipid modification of Yck2p, for prenylation, or possibly for palmitoylation.

* Corresponding author. Mailing address: Departments of Surgery and Pharmacology, Wayne State University School of Medicine, Elliman Building, Room 1205, 421 E. Canfield, Detroit, MI 48201. Phone: (313) 577-7807. Fax: (313) 577-7642. E-mail: ndavis{at}cmb.biosci.wayne.edu.

Molecular and Cellular Biology, July 2000, p. 5350-5359, Vol. 20, No. 14
0270-7306/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. J. Virol. Eukaryot. Cell
Microbiol. Mol. Biol. Rev. Clin. Vaccine Immunol. All ASM Journals

Copyright © 2000 by the American Society for Microbiology. All rights reserved.