AtVPS34, a phosphatidylinositol 3-kinase of Arabidopsis thaliana, is an essential protein with homology to a calcium-dependent lipid binding domain. |
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| Authors: | P Welters K Takegawa S D Emr M J Chrispeels |
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| Affiliation: | Department of Biology, University of California, San Diego, La Jolla 92093-0016. |
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| Abstract: | The cDNA encoding phosphatidylinositol (PI) 3-kinase was cloned from Arabidopsis thaliana, and the derived amino acid sequence (AtVPS34) has a significantly higher homology to yeast PI 3-kinase (VPS34) than to the mammalian (p110). The protein has two conserved domains: a catalytic site with the ATP-binding site near the C terminus and a calcium-dependent lipid-binding domain near the N terminus. The plant cDNA does not rescue a yeast vps34 deletion mutant, but a chimeric gene in which the coding sequence for the C-terminal third of VPS34 is replaced by the corresponding sequence from the plant gene does rescue the yeast mutant. PI 3-kinase activity is detectable in extracts from plants that overexpress the plant PI 3-kinase. Expression of antisense constructs gives rise to second-generation transformed plants severely inhibited in growth and development. |
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