DOLICHOL PHOSPHATE MANNOSE SYNTHASE1 Mediates the Biogenesis of Isoprenyl-Linked Glycans and Influences Development, Stress Response, and Ammonium Hypersensitivity in Arabidopsis  

Abstract

The most abundant posttranslational modification in nature is the attachment of preassembled high-mannose-type glycans, which determines the fate and localization of the modified protein and modulates the biological functions of glycosylphosphatidylinositol-anchored and N-glycosylated proteins. In eukaryotes, all mannose residues attached to glycoproteins from the luminal side of the endoplasmic reticulum (ER) derive from the polyprenyl monosaccharide carrier, dolichol P-mannose (Dol-P-Man), which is flipped across the ER membrane to the lumen. We show that in plants, Dol-P-Man is synthesized when Dol-P-Man synthase1 (DPMS1), the catalytic core, interacts with two binding proteins, DPMS2 and DPMS3, that may serve as membrane anchors for DPMS1 or provide catalytic assistance. This configuration is reminiscent of that observed in mammals but is distinct from the single DPMS protein catalyzing Dol-P-Man biosynthesis in bakers' yeast and protozoan parasites. Overexpression of DPMS1 in Arabidopsis thaliana results in disorganized stem morphology and vascular bundle arrangements, wrinkled seed coat, and constitutive ER stress response. Loss-of-function mutations and RNA interference-mediated reduction of DPMS1 expression in Arabidopsis also caused a wrinkled seed coat phenotype and most remarkably enhanced hypersensitivity to ammonium that was manifested by extensive chlorosis and a strong reduction of root growth. Collectively, these data reveal a previously unsuspected role of the prenyl-linked carrier pathway for plant development and physiology that may help integrate several aspects of candidate susceptibility genes to ammonium stress.

POLYPRENOL REDUCTASE2 Deficiency Is Lethal in Arabidopsis Due to Male Sterility

“…Similarly, increased Dol-P-Man biosynthesis results in an increased resistance of DPMS1-OE plants to tunicamycin (Jadid et al, 2011). It seems worth mentioning that neither of the mutant lines characterized in this study, pprd2-1 +/2 and pprd2-2 +/2 , showed hypersensitivity to ammonium salts (mentioned earlier; Jadid et al, 2011). This discrepancy could result from differences in the experimental conditions used.…”

“…Most probably an elevated Dol level compensates, at least partially, for the tunicamycin-induced disturbances in protein glycosylation, as clearly shown for pollen. Similarly, increased Dol-P-Man biosynthesis results in an increased resistance of DPMS1-OE plants to tunicamycin (Jadid et al, 2011). It seems worth mentioning that neither of the mutant lines characterized in this study, pprd2-1 +/2 and pprd2-2 +/2 , showed hypersensitivity to ammonium salts (mentioned earlier; Jadid et al, 2011).…”

“…Similarly, in Dol-P-Man synthase null mutants, reporter N-glycosylated and GPI-anchored proteins were affected (Jadid et al, 2011). The distinct phenotypes observed for various protein glycosylation-related mutants (Supplemental Table 6) are presumably caused by different degrees of hypoglycosylation of particular proteins.…”

Sugar availability modulates polyisoprenoid and phytosterol profiles in Arabidopsis thaliana hairy root culture

“…This phenomenon needs further studies of which identification and characterization of the polyprenol reductase(s) involved is the first indispensable step. The occurrence of a polyprenyl reductase (SRD5A3-like gene product) in Arabidopsis leaves has been reported recently [31] while its human counterpart had been characterized only one year earlier [22].…”

Reverse Transcription-PCR analysis of geranylgeranyl diphosphate synthase (JcGGPPS) in Jatropha curcas L. and in silico analysis of Casbene Synthase (JcCS) among Euphorbiaceae

“…All of these molecules possess many biological functions, including photosynthesis, cellular respiration, phytohormones, phytoalexins and pollination attractors [4]. In addition, they also serve as a central component of the cell membrane [5] and involved in the posttranslational protein modification [6]. A recent study has also demonstrated that terpenoids-derived molecules regulate polar auxin transport which plays an essential role in plant development [7].…”