AtKPNB1, an Arabidopsis importin-β protein, is downstream of the RING E3 ubiquitin ligase AtAIRP1 in the ABA-mediated drought stress response

• Published in: Planta 2020-11, Vol.252 (5), p.93-93, Article 93
• Main Authors: Oh, Tae Rin, Yu, Seong Gwan, Yang, Hee Woong, Kim, Jong Hum, Kim, Woo Taek
• Format: Article
• Language: English
• Subjects: Abscisic acid; Abscisic Acid - metabolism; Agriculture; Arabidopsis; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Biomedical and Life Sciences; Drought; Droughts; Ecology; Forestry; Germination; Life Sciences; Mutants; Mutation; Nuclear transport; Phenotypes; Plant Sciences; Progeny; Proteins; Seedlings; Short Communication; Stomata; Stress response; Stress, Physiological - genetics; Transportation systems; Ubiquitin; Ubiquitin-protein ligase; Ubiquitin-Protein Ligases - genetics; Ubiquitin-Protein Ligases - metabolism; Ubiquitination
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-020-03500-4

Main conclusion AtKPNB1, an Arabidopsis importin-β protein, was regulated by AtAIRP1 E3 ubiquitin ligase, which intensified the ABA-mediated drought stress response. As an early step in the abscisic acid (ABA)-mediated drought response, the ABA signal is transduced into the nucleus, and thus the nuclear transport system is crucially involved in the drought stress response. AtKPNB1, an importin-β protein, which is a core component of nuclear transport, was previously reported to be a negative factor in the ABA-mediated drought stress response (Luo et al. Luo et al., Plant J 75:377–389, 2013). Here, we report that AtAIPR1, an Arabidopsis RING-type E3 ubiquitin (Ub) ligase, interacted with and ubiquitinated AtKPNB1. A null mutation of AtKPNB1 suppressed the ABA-insensitive germination phenotype of atairp1 mutant seedlings as compared to that of the wild-type plants. Furthermore, the ABA-insensitive stomatal closure and drought-susceptible phenotypes of atairp1 were rescued in atairp1atkpnb1 double mutant progeny, indicating that AtKPNB1 functions downstream of AtAIRP1. These data suggest that AtAIRP1 regulates the ABA-mediated drought response in Arabidopsis via ubiquitination of AtKPNB1.