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SUMMARY Trichome development is a fascinating model to elaborate the plant cell differentiation and growth processes. A wealth of information has pointed to the contributions of the components associated with cell cycle control and ubiquitin/26S proteasome system (UPS) to trichome morphogenesis, but how these two pathways are connected remains obscure. Here, we report that HECT‐type ubiquitin ligase KAKTUS (KAK) targets the cyclin‐dependent kinase (CDK) inhibitor KRP2 (for kip‐related protein 2) for proteasome‐dependent degradation during trichome branching in Arabidopsis. We show that over‐expression ofKRP2promotes trichome branching and endoreduplication which is similar tokakloss of function mutants. KAK directly interacts with KRP2 and mediates KRP2 degradation. Mutation ofKAKresults in the accumulation of steady‐state KRP2. Consistently, inkak pKRP2:KRP2‐GFPplants, the trichome branching is further induced compared with the single mutant. Taken together, our studies bridge the cell cycle control and UPS pathways during trichome development and underscore the importance of post‐translational control in epidermal differentiation.
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Analysis of 26S Proteasome Activity across Arabidopsis Tissues
Plants utilize the ubiquitin proteasome system (UPS) to orchestrate numerous essential cellular processes, including the rapid responses required to cope with abiotic and biotic stresses. The 26S proteasome serves as the central catalytic component of the UPS that allows for the proteolytic degradation of ubiquitin-conjugated proteins in a highly specific manner. Despite the increasing number of studies employing cell-free degradation assays to dissect the pathways and target substrates of the UPS, the precise extraction methods of highly potent tissues remain unexplored. Here, we utilize a fluorogenic reporting assay using two extraction methods to survey proteasomal activity in different Arabidopsis thaliana tissues. This study provides new insights into the enrichment of activity and varied presence of proteasomes in specific plant tissues.
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- PAR ID:
- 10527653
- Publisher / Repository:
- Plants
- Date Published:
- Journal Name:
- Plants
- Volume:
- 13
- Issue:
- 12
- ISSN:
- 2223-7747
- Page Range / eLocation ID:
- 1696
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.3390/plants13121696
