Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024312 (lymphopenia)
 4,859 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

RT6.2 is a 26-kDa alloantigen expressed only on post-thymic T cells and attached to the cell membrane through a glycosylphosphatidylinositol (GPI) anchor. It has been reported that expression of RT6.2 in animal models may correlate with lymphopenia and genetically-induced insulin-dependent diabetes mellitus. Its physiological function is unclear. Since RT6.2 has significant amino acid identity with a GPI-anchored rabbit muscle NAD:arginine ADP-ribosyltransferase, RT6.2 was expressed in rat mammary adenocarcinoma cells and the ability of the expressed protein to catalyze ADP-ribose transfer reactions was examined. Cells transformed with the RT6.2 gene expressed NAD glycohydrolase activity that was released from intact cells by phosphatidylinositol-specific phospholipase C, consistent with its presence on the cell surface. A similar activity was not detected with vector-transformed cells. RT6.2 did not ADP-ribosylate simple guanidino compounds. The molecular weight of the phosphatidylinositol-specific phospholipase C-released NAD glycohydrolase, determined by SDS-polyacrylamide gel electrophoresis, was 22,000-24,000, in good agreement with that of native RT6.2. These results strongly suggest that the rat T cell alloantigen RT6.2 is a GPI-anchored NAD glycohydrolase.
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PMID:Expression of NAD glycohydrolase activity by rat mammary adenocarcinoma cells transformed with rat T cell alloantigen RT6.2. 814 25

Reticular dysgenesis is a human severe combined immunodeficiency that is primarily characterized by profound neutropenia and lymphopenia. The condition is caused by mutations in the adenylate kinase 2 (AK2) gene, resulting in the loss of mitochondrial AK2 protein expression. AK2 regulates the homeostasis of mitochondrial adenine nucleotides (ADP, ATP and AMP) by catalyzing the transfer of high-energy phosphate. Our present results demonstrate that AK2-knocked-down progenitor cells have poor proliferative and survival capacities and are blocked in their differentiation toward lymphoid and granulocyte lineages. We also observed that AK2 deficiency impaired mitochondrial function in general and oxidative phosphorylation in particular - showing that AK2 is critical in the control of energy metabolism. Loss of AK2 disrupts this regulation and leads to a profound block in lymphoid and myeloid cell differentiation.
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PMID:AK2 deficiency compromises the mitochondrial energy metabolism required for differentiation of human neutrophil and lymphoid lineages. 2627 Mar 50