| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Molecular and Cell Biology, Division of Biochemistry and Molecular Biology, University of California, Berkeley, CA 94720-3202, USA
Correspondence
Jeremy Thorner
jeremy{at}socrates.berkeley.edu
Saccharomyces cerevisiae Pkh1 and Pkh2 (orthologues of mammalian protein kinase, PDK1) are functionally redundant. These kinases activate three AGC family kinases involved in the maintenance of cell wall integrity: Ypk1 and Ypk2, two closely related, functionally redundant enzymes (orthologues of mammalian protein kinase SGK), and Pkc1 (orthologue of mammalian protein kinase PRK2). Pkh1 and Pkh2 activate Ypk1, Ypk2 and Pkc1 by phosphorylating a Thr in a conserved sequence motif (PDK1 site) within the activation loop of these proteins. A fourth protein kinase involved in growth control and stress response, Sch9 (orthologue of mammalian protein kinase c-Akt/PKB), also carries the conserved activation loop motif. Like other AGC family kinases, Ypk1, Ypk2, Pkc1 and Sch9 also carry a second conserved sequence motif situated in a region C-terminal to the catalytic domain, called the hydrophobic motif (PDK2 site). Currently, there is still controversy surrounding the identity of the enzyme responsible for phosphorylating this second site and the necessity for phosphorylation at this site for in vivo function. Here, genetic and biochemical methods have been used to investigate the physiological consequences of phosphorylation at the PDK1 and PDK2 sites of Ypk1, Pkc1 and Sch9. It was found that phosphorylation at the PDK1 site in the activation loop is indispensable for the essential functions of all three kinases in vivo, whereas phosphorylation at the PDK2 motif plays a non-essential and much more subtle role in modulating the ability of these kinases to regulate the downstream processes in which they participate.
Present address: Pinnacle BIO Consulting, 219 24th St, Del Mar, CA 92014, USA. This article has been cited by other articles:
|
|
 |
|
  H.-L. Ho, H.-Y. Lee, H.-C. Liao, and M.-Y. Chen Involvement of Saccharomyces cerevisiae Avo3p/Tsc11p in Maintaining TOR Complex 2 Integrity and Coupling to Downstream Signaling Eukaryot. Cell, August 1, 2008; 7(8): 1328 - 1343. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Lavoie and M. Whiteway Increased Respiration in the sch9{Delta} Mutant Is Required for Increasing Chronological Life Span but Not Replicative Life Span Eukaryot. Cell, July 1, 2008; 7(7): 1127 - 1135. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. M. Rubenstein and M. C. Schmidt Mechanisms Regulating the Protein Kinases of Saccharomyces cerevisiae Eukaryot. Cell, April 1, 2007; 6(4): 571 - 583. [Full Text] [PDF]
|
|
|
|
 |
|
 C. M. Wright, S. W. Fewell, M. L. Sullivan, J. M. Pipas, S. C. Watkins, and J. L. Brodsky The Hsp40 Molecular Chaperone Ydj1p, Along With the Protein Kinase C Pathway, Affects Cell-Wall Integrity in the Yeast Saccharomyces cerevisiae Genetics, April 1, 2007; 175(4): 1649 - 1664. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Daquinag, M. Fadri, S. Y. Jung, J. Qin, and J. Kunz The Yeast PH Domain Proteins Slm1 and Slm2 Are Targets of Sphingolipid Signaling during the Response to Heat Stress Mol. Cell. Biol., January 15, 2007; 27(2): 633 - 650. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. L. Brace, R. L. Lester, R. C. Dickson, and C. M. Rudin SVF1 Regulates Cell Survival by Affecting Sphingolipid Metabolism in Saccharomyces cerevisiae Genetics, January 1, 2007; 175(1): 65 - 76. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Bimbo, J. Liu, and M. K. Balasubramanian Roles of Pdk1p, a Fission Yeast Protein Related to Phosphoinositide-dependent Protein Kinase, in the Regulation of Mitosis and Cytokinesis Mol. Biol. Cell, July 1, 2005; 16(7): 3162 - 3175. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Liu, X. Zhang, R. L. Lester, and R. C. Dickson The Sphingoid Long Chain Base Phytosphingosine Activates AGC-type Protein Kinases in Saccharomyces cerevisiae Including Ypk1, Ypk2, and Sch9 J. Biol. Chem., June 17, 2005; 280(24): 22679 - 22687. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Kobayashi, H. Takematsu, T. Yamaji, S. Hiramoto, and Y. Kozutsumi Disturbance of Sphingolipid Biosynthesis Abrogates the Signaling of Mss4, Phosphatidylinositol-4-phosphate 5-Kinase, in Yeast J. Biol. Chem., May 6, 2005; 280(18): 18087 - 18094. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Duran and C. Nombela Fungal cell wall biogenesis: building a dynamic interface with the environment Microbiology, October 1, 2004; 150(10): 3099 - 3103. [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |
