The pleiotropic role of the 26S proteasome subunit RPN10 in Arabidopsis growth and development supports a substrate-specific function in abscisic acid signaling.
The 26S proteasome is an essential protease complex responsible for removing most short-lived intracellular proteins, especially those modified with polyubiquitin chains. We show here that an Arabidopsis mutant expressing an altered RPN10 subunit exhibited a pleiotropic phenotype consistent with specific changes in 26S proteasome function. rpn10-1 plants displayed reduced seed germination, growth rate, stamen number, genetic transmission through the male gamete, and hormone-induced cell division, which can be explained partially by a constitutive downregulation of the key cell cycle gene CDKA;1. rpn10-1 also was more sensitive to abscisic acid (ABA), salt, and sucrose stress and to DNA-damaging agents and had decreased sensitivity to cytokinin and auxin. Most of the phenotypes can be explained by a hypersensitivity to ABA, which is reflected at the molecular level by the selective stabilization of the short-lived ABA-signaling protein ABI5. Collectively, these results indicate that RPN10 affects a number of regulatory processes in Arabidopsis likely by directing specific proteins to the 26S proteasome for degradation. A particularly important role may be in regulating the responses to signals promulgated by ABA.
Smalle
Jan
J
Department of Horticulture and Cellular and Molecular Biology Program, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Kurepa
Jasmina
J
Yang
Peizhen
P
Emborg
Thomas J
TJ
Babiychuk
Elena
E
Kushnir
Sergei
S
Vierstra
Richard D
RD
D000040:Abscisic Acid / Q000494:pharmacology*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D050976:Basic-Leucine Zipper Transcription Factors; D003432:Cross-Linking Reagents / Q000494:pharmacology; D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage / Q000187:drug effects / Q000528:radiation effects; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D005816:Genetic Complementation Test; D018525:Germination / Q000187:drug effects / Q000528:radiation effects; D007210:Indoleacetic Acids / Q000494:pharmacology; D016685:Mitomycin / Q000494:pharmacology; D009154:Mutation; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D046988:Proteasome Endopeptidase Complex; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D015398:Signal Transduction; D012965:Sodium Chloride / Q000494:pharmacology; D013379:Substrate Specificity; D013395:Sucrose / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014466:Ultraviolet Rays
C409743:ABI5 protein, Arabidopsis; D029681:Arabidopsis Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D003432:Cross-Linking Reagents; D007210:Indoleacetic Acids; D021122:Protein Subunits; C475163:RPN10 protein, Arabidopsis; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D012965:Sodium Chloride; D016685:Mitomycin; D013395:Sucrose; D000040:Abscisic Acid; C434472:CDKA1 protein, Arabidopsis; D018844:Cyclin-Dependent Kinases; D010447:Peptide Hydrolases; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease