High impact information on PGM

• This platform was used to analyze the diurnal changes of enzyme activities in wild-type Columbia-0 (Col-0) and the starchless plastid phosphoglucomutase (pgm) mutant, and in Col-0 during a prolongation of the night [1].
• Taken together, the results suggest that ARG1 and ARL2 function in the same gravity signal transduction pathway in the hypocotyl and root of Arabidopsis seedlings, distinct from the pathway involving PGM [2].
• The ARG1-LIKE2 gene of Arabidopsis functions in a gravity signal transduction pathway that is genetically distinct from the PGM pathway [2].
• Our results indicate that plastidic PGM is an important factor affecting carbon flux in triacylglycerol accumulation in oilseed plants, most likely through its essential role in starch synthesis [3].
• The Calvin cycle intermediates fructose-1,6-bisphosphate and ribulose-1, 5-bisphosphate exerted an inhibitory effect on PGM activity, supporting its proposed involvement in controlling photosynthetic carbon flow [3].

Biological context of PGM

• Analysis of the phosphoglucomutase and shoot gravitropism 2-1 mutants revealed that the sedimenting amyloplasts in the leaf petiole are important for gravity perception, as is the case in stems and roots [4].
• An Arabidopsis EST that showed significant homology to the cytosolic isoform of phosphoglucomutase (PGM) from maize was able to complement the mutant phenotype [5].

Anatomical context of PGM

• An Arabidopsis cDNA (AtPGMp) encoding the plastidic phosphoglucomutase (PGM) predicted a 623-amino acid protein with an N-terminal sequence typical of a plastid signal peptide [3].

Associations of PGM with chemical compounds

• The substrate for PGM, glucose 6-phosphate, accumulated in stf1 during the day, resulting in 10-fold higher content than in the wild type at the end of the photoperiod [5].
• Furthermore, we discovered that the AtPGM promoter was down-regulated by abscisic acid and hydroxyurea, whereas it was induced by sucrose, oryzalin, and auxin, thereby revealing expression characteristics typical of genes with roles in meristematic cells [6].
• To test this hypothesis, we have compared the ADPG content in both Arabidopsis and potato wild-type (WT) leaves with those of the starch-deficient mutants with reduced pPGM and AGP [7].

Other interactions of PGM

• Some enzyme activity QTLs mapped very close to known enzyme-encoding loci (e.g., hexokinase, PGI, and PGM) [8].
• Assessment of the auxin-inducible AUX1 gene promoter (a gene coding for a polar auxin transport protein) similarly revealed feeding cell and meristem expression, suggesting that auxin may be responsible for the observed tissue specificity of the AtPGM promoter [6].

Analytical, diagnostic and therapeutic context of PGM

• Allelism tests with known mutants showed that stf1 represents a new mutant allele of the plastid isoform of the enzyme phosphoglucomutase (PGMp) [5].
• Gravitropism was studied in seedlings of Nicotiana sylvestris Speg. et Comes wild-type (WT) and mutant NS 458 which has a defective plastid phosphoglucomutase (EC 2.7.5.1.). Starch was greatly reduced in NS 458 compared to the WT, but small amounts of starch were detected in rootcap columella cells in NS 458 by light and electron microscopy [9].

References