Journal Article

Hexokinase as a sugar sensor in higher plants

Sheen, J, Leon, P, Jang, J.C. (Massachusetts General Hospital, Boston, MA.), Zhou, L

1997

Overview

The mechanisms by which higher plants recognize and respond to sugars are largely unknown. Here, we present evidence that the first enzyme in the hexose assimilation pathway, hexokinase (HXK), acts as a sensor for plant sugar responses. Transgenic Arabidopsis plants expressing antisense hexokinase (AtHXK) genes are sugar hyposensitive, whereas plants overexpressing AtHXK are sugar hypersensitive. The transgenic plants exhibited a wide spectrum of altered sugar responses in seedling development and in gene activation and repression. Furthermore, overexpressing the yeast sugar sensor YHXK2 caused a dominant negative effect by elevating HXK catalytic activity but reducing sugar sensitivity in transgenic plants. The result suggests that HXK is a dual-function enzyme with a distinct regulatory function not interchangeable between plants and yeast

• Publisher: American Society of Plant Physiologists
• Subject: ADN / Amino Acid Sequence / amino acid sequences / Animals / antisense DNA / Arabidopsis / Arabidopsis - enzymology / Arabidopsis - genetics / Arabidopsis - growth & development / ARABIDOPSIS THALIANA / ARN MENSAJERO / ARN MESSAGER / biological resistance / Carbohydrate Metabolism / Carbohydrates / Carbohydrates - pharmacology / CARTE GENETIQUE / Chromosome Mapping / complementary DNA / COMPOSICION QUIMICA / COMPOSITION CHIMIQUE / CRECIMIENTO / CROISSANCE / enzymology / ETAPAS DE DESARROLLO DE LA PLANTA / EXPRESION GENICA / EXPRESSION DES GENES / FENOTIPOS / FISIOLOGIA VEGETAL / GENE / Gene Expression / Gene expression regulation / GENES / Genes, Plant / Genetic Complementation Test / GENETICA / genetics / GENETIQUE / GLUCOSA / GLUCOSE / growth & development / HEXOKINASE / Hexokinase - genetics / Hexokinase - metabolism / HEXOQUINASA / Humans / MAPAS GENETICOS / messenger RNA / metabolism / METABOLISME DES GLUCIDES / METABOLISMO DE CARBOHIDRATOS / Molecular Sequence Data / nucleotide sequences / pharmacology / PHENOTYPE / PHYSIOLOGIE VEGETALE / Plant cells / plant development / PLANTAS TRANSGENICAS / PLANTE TRANSGENIQUE / Plants / Plants, Genetically Modified / PLANTULAS / PLANTULE / Rats / Repression / Saccharomyces cerevisiae / Saccharomyces cerevisiae - enzymology / Saccharomyces cerevisiae - genetics / SECUENCIA NUCLEOTIDICA / seedling growth / Seedlings / Sensors / Sequence Homology, Amino Acid / SEQUENCE NUCLEOTIDIQUE / Species Specificity / STADE DE DEVELOPPEMENT VEGETAL / structural genes / Sugars / Transgenic plants / Yeasts