The Antioxidant Enzyme Prdx1 Controls Neuronal Differentiation by Thiol-Redox-Dependent Activation of GDE2

Abstract

Summary The six-transmembrane protein GDE2 comprises a new signaling system that controls the onset and progression of spinal motor neuron differentiation through extracellular glycerophosphodiester phosphodiesterase metabolism. However, the mechanisms that regulate its activity are unknown. Here we show that the antioxidant scavenger Peroxiredoxin1 (Prdx1) interacts with GDE2, and that loss of Prdx1 causes motor neuron deficits analogous to GDE2 ablation. Prdx1 cooperates with GDE2 to drive motor neuron differentiation, and this synergy requires Prdx1 thiol-dependent catalysis. Prdx1 activates GDE2 through reduction of an intramolecular disulfide bond bridging its intracellular N- and C-terminal domains that normally gates GDE2 activity. GDE2 variants incapable of disulfide bond formation acquire independence from Prdx1, and are potent inducers of motor neuron differentiation. These findings define Prdx1 as a pivotal regulator of GDE2 activity, and reveal critical roles for coupled thiol redox-dependent cascades in controlling neuronal differentiation in the spinal cord.

High NaCl- and urea-induced posttranslational modifications that increase glycerophosphocholine by inhibiting GDPD5 phosphodiesterase

“…(22) are mainly perinuclear, consistent with location in the endoplasmic reticulum, although the stain pattern does not fully coincide with that of the endoplasmic reticulum marker calnexin (16). Mouse GDPD5-V5 was also reported to be perinuclear in HEK293 cells (6), whereas, in contrast, chicken GDPD5-FLAG was reported to be at the periphery of the same cells (12). In the present studies, we find that both chicken GDPD5-FLAG and mouse GDPD5-V5 are perinuclear in subconfluent HeLa cells, but that some mouse GDPD5 also localizes to the periphery of confluent cells (Fig.…”

“…GDPD5 contains many predicted membranespanning regions (10,16). However, although mouse GDPD5-V5 is located in the region of the endoplasmic reticulum of HEK293 cells (6), chicken GDPD5-FLAG is located in the plasma membrane in chicken neurons and in HEK293 cells (12). Given the high amino acid identity of chicken and mouse GDPD5, different subcellular localizations seemed surprising, so we visualized their subcellular location simultaneously in HeLa cells.…”

“…Apparently, when the cells are confluent, recombinant GDPD5 may localize to the plasma membrane, as well as to the endoplasmic reticulum. Based on the effect of cellular permeabilization on staining of different parts of it, chicken GDPD5 in plasma membranes is oriented with its conserved GDPD site facing outward and its N-and C-terminal ends facing inward (12). It is difficult to imagine how GPC-PDE activity of an outward-facing GDPD site could affect intracellular GPC.…”

“…cells (6, 7) and differentiation of progenitor motor neurons (12). GDPD activity of GDPD5 contributes to osmotic regulation of GPC in epithelial cells by affecting the rate at which an intracellular substrate, GPC, is degraded (6).…”

“…Because mutation of a crucial histidine in the putative site to alanine eliminates the effect of GDPD5 on neuronal differentiation, GDPD activity was deemed to be necessary (10). Using neuronal differentiation as the end point, the antioxidant scavenger peroxiredoxin (Prdx1) was found to activate GDPD5 by a thiol-redox-dependent reaction (12). Prdx1 activates GDPD5 through reduction of an intramolecular disulfide bond that bridges intramolecular N-and C-terminal domains (cysteine 25-576).…”