Abstract

We report that protein phosphorylation is involved in the control of starch metabolism in Arabidopsis leaves at night. sex4 ( starch excess 4) mutants, which have strongly reduced rates of starch metabolism, lack a protein predicted to be a dual specificity protein phosphatase. We have shown that this protein is chloroplastic and can bind to glucans and have presented evidence that it acts to regulate the initial steps of starch degradation at the granule surface. Remarkably, the most closely related protein to SEX4 outside the plant kingdom is laforin, a glucan-binding protein phosphatase required for the metabolism of the mammalian storage carbohydrate glycogen and implicated in a severe form of epilepsy ( Lafora disease) in humans.

Published in

Journal of Biological Chemistry
2006, Volume: 281, number: 17, pages: 11815-11818
Publisher: AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

UKÄ Subject classification

Botany


Publication identifier

DOI: https://doi.org/10.1074/jbc.M600519200

Permanent link to this page (URI)

https://res.slu.se/id/publ/42703