Molecular characterization of At5PTase1, an inositol phosphatase capable of terminating inositol trisphosphate signaling

Citation
Se. Berdy et al., Molecular characterization of At5PTase1, an inositol phosphatase capable of terminating inositol trisphosphate signaling, PLANT PHYSL, 126(2), 2001, pp. 801-810
Citations number
39
Categorie Soggetti
Plant Sciences","Animal & Plant Sciences
Journal title
PLANT PHYSIOLOGY
ISSN journal
00320889 → ACNP
Volume
126
Issue
2
Year of publication
2001
Pages
801 - 810
Database
ISI
SICI code
0032-0889(200106)126:2<801:MCOAAI>2.0.ZU;2-6
Abstract
The inositol triyhosphate (IP3)-signaling pathway has been associated with several developmental and physiological processes in plants, but we current ly know little about the regulation of this pathway. Inositol 5 ' phosphata ses (5PTases) are enzymes that remove a 5 ' phosphate from several potentia l second messengers, including IP3. In catalyzing the removal of a 5 ' phos yhate from second messenger substrates, 5PTases can act to terminate signal transduction events. We describe the molecular analysis of At5PTasel, a 5P Tase gene from Arabidopsis. When expressed transiently in Arabidopsis leaf tissue or ectopically in transgenic plants, At5PTasel allowed for the incre ased hydrolysis of I(1,4,5)P-3 and I(1,3,4,5)P-4 substrates. At5PTase1 did not hydrolyze I(1)P, I(1,4)P-2, or PI(4,5)P-2 substrates. This substrate sp ecificity was similar to that of the human Type I 5PTase. We identified 14 other potential At5PTase genes and constructed an unrooted phylogenetic tre e containing putative Arabidopsis, human, and yeast 5PTase proteins. This a nalysis indicated that the Arabidopsis 5PTases were grouped in two separate branches of the tree. The multiplicity of At5PTases indicates that these e nzymes may have different substrate specificities and play different roles in signal termination in Arabidopsis.