Differential Expression Patterns of NDRG Family Proteins in the Central Nervous System

Abstract

S U M M A R Y The N-myc downstream-regulated gene (NDRG) family consists of four proteins: NDRG1, NDRG2, NDRG3, and NDRG4 in mammals. NDRG1 has been thoroughly studied as an intracellular protein associated with stress response, cell growth, and differentiation. A nonsense mutation in the NDRG1 gene causes hereditary motor and sensory neuropathy, Charcot-Marie-Tooth disease type 4D. We previously generated Ndrg1-deficient mice and found that they exhibited peripheral nerve degeneration caused by severe demyelination, but that the complicated motor abilities were retained. These results implied that other NDRG family proteins may compensate for the NDRG1 deficiency in the central nervous system. In this study we raised specific antibodies against each member of the NDRG protein family and examined their cellular expression patterns in the mouse brain. In the cerebrum, NDRG1 and NDRG2 were localized in oligodendrocytes and astrocytes, respectively, whereas NDRG3 and NDRG4 were ubiquitous. In the cerebellum, NDRG1 and NDRG4 were localized in Purkinje cells and NDRG2 in Bergmann glial cells. NDRG3 was detected in the nuclei in most cells. These expression patterns demonstrated the cell type-specific and ubiquitous localization of the NDRG family proteins. Each NDRG may play a partially redundant role in specific cells in the brain. (J Histochem Cytochem 56:175-182, 2008)

NDRG4 Protein-deficient Mice Exhibit Spatial Learning Deficits and Vulnerabilities to Cerebral Ischemia

“…NDRG4 expression was mainly observed in NeuN-positive cells but not in GFAP-positive cells, indicating that NDRG4 was specifically expressed in neurons. This was consistent with our previous finding that NDRG4 protein was expressed in neurons of the cerebral cortex and Purkinje cells of the cerebellum (17).…”

“…Anti-NDRG2, anti-NDRG3, and anti-NDRG4 rabbit antisera were raised against the synthetic peptides Q 351 SSESGTLPSGPPGH 365 for mouse NDRG2 (17), F 343 SRSVTSNQSDGTQE 357 for mouse NDRG3 (17), and C-N 214 RPGTVPNAKTLR 226 -CONH 2 for mouse NDRG4, respectively, which were conjugated with keyhole limpet hemocyanin. Polyclonal antibodies in the antisera were purified by antigen-immobilized affinity column chromatography.…”

“…However, information on the physiological function of NDRG4 is lacking. In the mouse brain, NDRG4 is identified in the neuronal cytoplasm of the cerebrum and cerebellum (17). Down-regulation of NDRG4 in PC12 cells results in extending shorter neurites in response to NGF (18).…”

Behavioral and biochemical dissociation of arousal and homeostatic sleep need influenced by prior wakeful experience in mice

“…Furthermore, we have shown that the level of hyperphosphorylated forms of NDRG2 protein is increased in the diencephalic samples from mice with increased homeostatic sleep need. NDRG2 is an astrocytic protein (29) of which the cellular function is poorly characterized. NDRG2 may be a substrate for a number of protein kinases, and our preliminary data indicate that the hyper-phosphorylated NDRG2 spots are recognized by antibodies against Akt substrates as well as by those against PKC substrates (Fig.…”

“…Protein differential display was carried out using a 2D-DIGE system (GE Healthcare), and target protein spots were identified by nano-liquid chromatography-tandem mass spectrometry (nano-LC/MS/MS) operated by the UTSW Protein Chemistry Technology Center. Confirmation of 2D-DIGE results was performed by 1D Western blot using phosphorylated protein and total protein samples against anti-DNM1 (Abcam) and anti-NDRG2 antibodies (29). Values were then expressed relative to the β-tubulin.…”