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Three SAC1 ‐like genes show overlapping patterns of expression in Arabidopsis but are remarkably silent during embryo development
Author(s) -
Despres Barbara,
Bouissonnié Fabrice,
Wu HuiJu,
Gomord Véronique,
Guilleminot Jocelyne,
Grellet Françoise,
Berger Frédéric,
Delseny Michel,
Devic Martine
Publication year - 2003
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2003.01720.x
Subject(s) - biology , arabidopsis , saccharomyces cerevisiae , gene , arabidopsis thaliana , genetics , yeast , microbiology and biotechnology , inositol , mutant , endoplasmic reticulum , signal transduction , receptor
Summary In Saccharomyces cerevisiae , the SAC1 gene encodes a polyphosphoinositide phosphatase (PPIPase) that modulates the levels of phosphoinositides, which are key regulators of a number of signal transduction processes. SAC1p has been implicated in multiple cellular functions: actin cytoskeleton organization, secretory functions, inositol metabolism, ATP transport, and multiple‐drug sensitivity. Here, we describe the characterization of three genes in Arabidopsis thaliana , AtSAC1a , AtSAC1b , and AtSAC1c, encoding proteins similar to those of yeast SAC1p. We demonstrated that the three AtSAC1 proteins are functional homologs of the yeast SAC1p because they can rescue the cold‐sensitive and inositol auxotroph yeast sac1 ‐null mutant strain. The fact that Arabidopsis and yeast SAC1 genes derived from a common ancestor suggests that this plant multigenic family is involved in the phosphoinositide pathway and in a range of cellular functions similar to those in yeast. Using GFP fusion experiments, we demonstrate that the three AtSAC1 proteins are targeted to the endoplasmic reticulum. Their expression patterns are overlapping, with at least two members expressed in each organ. Remarkably, AtSAC1 genes are not expressed during seed development, and therefore additional phosphatases are required to control phosphoinositide levels in seeds.