Abstract
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.
Original language | English |
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Pages (from-to) | 579-589 |
Number of pages | 11 |
Journal | Cell |
Volume | 127 |
Issue number | 3 |
DOIs | |
Publication status | Published - 2006 Nov 3 |
Bibliographical note
Funding Information:We are grateful to H. Sze for generously providing VHA antibodies and stimulating discussions and Sheen Lab members for helpful comments on the manuscript. We thank the Salk Institute Genomic Analysis Laboratory for providing the sequence-indexed Arabidopsis T-DNA insertion mutants, and ABRC for providing vha-C seeds. This work was supported by grants from the NSF (IOB-0217191 and DBI-0077692) and NIH (R01 GM060493) to J.S.
ASJC Scopus subject areas
- General Biochemistry,Genetics and Molecular Biology