Regulatory functions of nuclear hexokinase1 complex in glucose signaling.
Arabidopsis hexokinase1 (HXK1) is a glucose sensor that integrates nutrient and hormone signals to govern gene expression and plant growth in response to environmental cues. How the metabolic enzyme mediates glucose signaling remains a mystery. By coupling proteomic and binary-interaction screens, we discover two nuclear-specific HXK1 unconventional partners: the vacuolar ... H(+)-ATPase B1 (VHA-B1) and the 19S regulatory particle of proteasome subunit (RPT5B). Remarkably, vha-B1 and rpt5b mutants uniquely share a broad spectrum of glucose response defects with the HXK1 mutant gin2 (glucose-insensitive2). Genetic and chromatin immunoprecipitation analyses suggest that the nuclear HXK1 forms a glucose signaling complex core with VHA-B1 and RPT5B that directly modulates specific target gene transcription independent of glucose metabolism. The findings support a model in which conserved metabolic enzymes and proteins of well-established activities may perform previously unrecognized nuclear functions.
Mesh Terms:
Arabidopsis, Cell Nucleus, Gene Expression Regulation, Plant, Glucose, Hexokinase, Models, Biological, Nuclear Proteins, Proteomics, Signal Transduction
Arabidopsis, Cell Nucleus, Gene Expression Regulation, Plant, Glucose, Hexokinase, Models, Biological, Nuclear Proteins, Proteomics, Signal Transduction
Cell
Date: Nov. 03, 2006
PubMed ID: 17081979
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