Fig. 7: Maintenance of BIK1 homeostasis by interplay between RGLG1/2 and PUB25/26 in Arabidopsis. | Nature Communications

Fig. 7: Maintenance of BIK1 homeostasis by interplay between RGLG1/2 and PUB25/26 in Arabidopsis.

From: BIK1 protein homeostasis is maintained by the interplay of different ubiquitin ligases in immune signaling

Fig. 7: Maintenance of BIK1 homeostasis by interplay between RGLG1/2 and PUB25/26 in Arabidopsis.The alternative text for this image may have been generated using AI.

a RGLG1/2 suppress PUB25-mediated BIK1 degradation. BIK1 functions as an immune signaling hub and is associated with the FLS2-BAK1 receptor complex. BIK1 is mainly present in a hypo-phosphorylated form in the resting state; upon flg22 perception, BIK1 is hyper-phosphorylated. Two ubiquitin ligases PUB25/26 ubiquitinate the hypo-phosphorylated BIK1 and mediate its degradation. We proposed a model for maintenance of BIK1 homeostasis by interplay of different ubiquitin ligases. Two closely related RING-type ubiquitin ligases RGLG1 and RGLG2 specifically interact with the hypo-phosphorylated BIK1 and directly ubiquitinate BIK1. PUB25 mediates the degradation of RGLG2, and RGLG2 in turn suppresses the ubiquitin ligase of PUB25. RGLG1/2 suppress BIK1 degradation mediated by PUB25, promote BIK1 accumulation, and positively regulate immune signaling. b BIK1 protein accumulation is lower in rglg1 rglg2 than in Col-0, and the immune responses are weaker in rglg1 rglg2 than in Col-0.

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