Characterization of Regulatory Events Associated with Membrane Targeting of p90 Ribosomal S6 Kinase 1
Open Access
- 1 November 2001
- journal article
- Published by Informa UK Limited in Molecular and Cellular Biology
- Vol. 21 (21), 2324-2331
- https://doi.org/10.1128/mcb.21.21.7470-7480.2001
Abstract
Ubiquitin-dependent proteolysis plays a pivotal role in stress responses. To investigate the mechanisms of these cellular processes, we have been studying Schizosaccharomyces pombe mutants that have altered sensitivities to various stress conditions. Here, we showed that Lub1, a homologue of Ufd3p/Zzz4p/Doa1p in budding yeast, is involved in the regulation of ubiquitin contents. Disruption of the lub1+ gene resulted in monoubiquitin as well as multiubiquitin depletion without change in mRNA level and in hypersensitivity to various stress conditions. Consistently, overexpression of genes encoding ubiquitin suppressed the defects associated with lub1 mutation, indicating that the phenotypes of the lub1 mutants under stress conditions were due to cellular ubiquitin shortage at the posttranscriptional level. In addition, the lub1-deleted cells showed aberrant functions in ubiquitin/proteasome-dependent proteolysis, with accelerated degradation of ubiquitin. Also Cdc48, a stress-induced chaperon-like essential ATPase, was found to interact with Lub1, and this association might contribute to the stabilization of Lub1. Our results indicated that Lub1 is responsible for ubiquitin homeostasis at the protein level through a negative regulation of ubiquitin degradation.Keywords
This publication has 43 references indexed in Scilit:
- Phosphorylation of Rat Serine 105 or Mouse Threonine 217 in C/EBPβ Is Required for Hepatocyte Proliferation Induced by TGFαMolecular Cell, 1999
- Induction of Metaphase Arrest in Cleaving Xenopus Embryos by the Protein Kinase p90 RskScience, 1999
- The Protein Kinase p90 Rsk as an Essential Mediator of Cytostatic Factor ActivityScience, 1999
- 90-kDa Ribosomal S6 Kinase Is Phosphorylated and Activated by 3-Phosphoinositide-dependent Protein Kinase-1Journal of Biological Chemistry, 1999
- p90RSK Is a Serum-stimulated Na+/H+ Exchanger Isoform-1 KinasePublished by Elsevier BV ,1999
- AKT/PKB and Other D3 Phosphoinositide-Regulated Kinases: Kinase Activation by Phosphoinositide-Dependent PhosphorylationAnnual Review of Biochemistry, 1999
- Intracellular signalling: PDK1 – a kinase at the hub of thingsCurrent Biology, 1999
- Regulation of protein kinase C ζ by PI 3-kinase and PDK-1Current Biology, 1998
- Identification of Serine 380 as the Major Site of Autophosphorylation of Xenopus pp90rskBiochemical and Biophysical Research Communications, 1997
- Coupling of the RAS-MAPK Pathway to Gene Activation by RSK2, a Growth Factor-Regulated CREB KinaseScience, 1996