Expression of 1L-Myoinositol-1-Phosphate Synthase in Organelles1
AUTOR(ES)
Lackey, Kimberly Helms
FONTE
The American Society for Plant Biologists
RESUMO
We have studied the expression of 1l-myoinositol-1-phosphate synthase (MIPS; EC 5.5.1.4) in developing organs of Phaseolus vulgaris to define genetic controls that spatially regulate inositol phosphate biosynthesis. MIPS, the pivotal biosynthetic enzyme in inositol metabolism, is the only enzyme known to catalyze the conversion of glucose 6-phosphate to inositol phosphate. It is found in unicellular and multicellular eukaryotes and has been isolated as a soluble enzyme from both. Thus, it is widely accepted that inositol phosphate biosynthesis is largely restricted to the cytosol. Here, we report findings that suggest the enzyme is also expressed in membrane-bound organelles. Microscopic and biochemical analyses detected MIPS expression in plasma membranes, plastids, mitochondria, endoplasmic reticula, nuclei, and cell walls of bean. To address mechanisms by which the enzyme could be targeted to or through membranes, MIPS genes were analyzed for sorting signals within primary structures and upstream open reading frames that we discovered through our sequence analyses. Comprehensive computer analyses revealed putative transit peptides that are predicted to target the enzyme to different cellular compartments. Reverse transcriptase PCR experiments suggest that these putative targeting peptides are expressed in bean roots and leaves.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=181307Documentos Relacionados
- 1 L-myo-Inositol 1-Phosphate Synthase from Arabidopsis thaliana.
- Chloroplast as a Locale of L-myo-Inositol-1-Phosphate Synthase 1
- L-myo-InositoL-1- phosphate synthase from bryophytes: purification and characterization of the enzyme from Lunularia cruciata (L.) Dum
- The arabidopsis thaliana myo-inositol 1-phosphate synthase (EC 5.5.1.4).
- Purification of myo-Inositol 1-Phosphate Synthase from Rice Cell Culture by Affinity Chromatography 1