A short motif in Arabidopsis CDK inhibitor ICK1 decreases the protein level, probably through a ubiquitin-independent mechanism
| Autor: | Sheng Wang, Xianzong Shi, Shengjian Ye, Qin Li, Ron Chan, Hong Wang, Troy A. A. Harkness |
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| Rok vydání: | 2015 |
| Předmět: |
0301 basic medicine
Leupeptins Amino Acid Motifs Green Fluorescent Proteins Arabidopsis Plant Science Ubiquitin-conjugating enzyme Green fluorescent protein 03 medical and health sciences Ubiquitin Cyclin-dependent kinase Gene Expression Regulation Plant Yeasts Genetics Cyclin-Dependent Kinase Inhibitor Proteins 2. Zero hunger biology Arabidopsis Proteins Protein Stability Temperature Cell Biology Cullin Proteins Plants Genetically Modified Protein ubiquitination 030104 developmental biology Biochemistry Proteasome Mutation biology.protein Sequence motif CDK inhibitor |
| Zdroj: | The Plant journal : for cell and molecular biology. 87(6) |
| ISSN: | 1365-313X |
| Popis: | The ICK/KRP family of cyclin-dependent kinase (CDK) inhibitors modulates the activity of plant CDKs through protein binding. Previous work has shown that changing the levels of ICK/KRP proteins by overexpression or downregulation affects cell proliferation and plant growth, and also that the ubiquitin proteasome system is involved in degradation of ICK/KRPs. We show in this study that the region encompassing amino acids 21 to 40 is critical for ICK1 levels in both Arabidopsis and yeast. To determine how degradation of ICK1 is controlled, we analyzed the accumulation of hemagglutinin (HA) epitope-tagged ICK1 proteins in yeast mutants defective for two ubiquitin E3 ligases. The highest level of HA-ICK1 protein was observed when both the N-terminal 1-40 sequence was removed and the SCF (SKP1-Cullin1-F-box complex) function disrupted, suggesting the involvement of both SCF-dependent and SCF-independent mechanisms in the degradation of ICK1 in yeast. A short motif consisting of residues 21-30 is sufficient to render green fluorescent protein (GFP) unstable in plants and had a similar effect in plants regardless of whether it was fused to the N-terminus or C-terminus of GFP. Furthermore, results from a yeast ubiquitin receptor mutant rpn10Δ indicate that protein ubiquitination is not critical in the degradation of GFP-ICK1(1-40) in yeast. These results thus identify a protein-destabilizing sequence motif that does not contain a typical ubiquitination residue, suggesting that it probably functions through an SCF-independent mechanism. |
| Databáze: | OpenAIRE |
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