title: Modulation of phototropic responsiveness in Arabidopsis through ubiquitination of phototropin 1 by the CUL3-Ring E3 ubiquitin ligase CRL3(NPH3).
abstract: Plant phototropism is an adaptive response to changes in light direction, quantity, and quality that results in optimization of photosynthetic light harvesting, as well as water and nutrient acquisition. Though several components of the phototropic signal response pathway have been identified in recent years, including the blue light (BL) receptors phototropin1 (phot1) and phot2, much remains unknown. Here, we show that the phot1-interacting protein NONPHOTOTROPIC HYPOCOTYL3 (NPH3) functions as a substrate adapter in a CULLIN3-based E3 ubiquitin ligase, CRL3(NPH3). Under low-intensity BL, CRL3(NPH3) mediates the mono/multiubiquitination of phot1, likely marking it for clathrin-dependent internalization from the plasma membrane. In high-intensity BL, phot1 is both mono/multi- and polyubiquitinated by CRL3(NPH3), with the latter event targeting phot1 for 26S proteasome-mediated degradation. Polyubiquitination and subsequent degradation of phot1 under high-intensity BL likely represent means of receptor desensitization, while mono/multiubiquitination-stimulated internalization of phot1 may be coupled to BL-induced relocalization of hormone (auxin) transporters.
authors: Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211, USA.
authors: Diana
authors: D
authors: Roberts
authors: Ullas V
authors: UV
authors: Pedmale
authors: Johanna
authors: J
authors: Morrow
authors: Shrikesh
authors: S
authors: Sachdev
authors: Esther
authors: E
authors: Lechner
authors: Xiaobo
authors: X
authors: Tang
authors: Ning
authors: N
authors: Zheng
authors: Mark
authors: M
authors: Hannink
authors: Pascal
authors: P
authors: Genschik
authors: Emmanuel
authors: E
authors: Liscum
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002522:Chlorocebus aethiops; D044842:Cullin Proteins; D007210:Indoleacetic Acids / Q000378:metabolism; D007915:Lepidoptera; D008027:Light; D055537:Light Signal Transduction / Q000502:physiology* / Q000528:radiation effects; D009154:Mutation; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D056949:Phototropins / Q000235:genetics / Q000378:metabolism; D018524:Phototropism / Q000502:physiology* / Q000528:radiation effects; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D059748:Proteolysis; D036226:Seedlings / Q000166:cytology / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism; D054875:Ubiquitination / Q000502:physiology* / Q000528:radiation effects
chemical_list: C500789:AT1G26830 protein, Arabidopsis; D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D044842:Cullin Proteins; D007210:Indoleacetic Acids; C400222:NPH3 protein, Arabidopsis; D010750:Phosphoproteins; D056949:Phototropins; C500790:cullin 3B protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases; C103646:NPH1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease