A Ca(2+)-activated NADPH oxidase in testis, spleen, and lymph nodes

Banfi, Botond; Molnar, Gergely; Maturana, Andrés; Steger, Klaus; Hegedus, B.; Demaurex, Nicolas; Krause, Karl-Heinz

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Title		A Ca(2+)-activated NADPH oxidase in testis, spleen, and lymph nodes
Authors		Banfi, Botond Molnar, Gergely Maturana, Andrés Steger, Klaus Hegedus, B. Demaurex, Nicolas Krause, Karl-Heinz
Published in		Journal of Biological Chemistry. 2001, vol. 276, no. 40, p. 37594-37601
Abstract		Superoxide and its derivatives are increasingly implicated in the regulation of physiological functions from oxygen sensing and blood pressure regulation to lymphocyte activation and sperm-oocyte fusion. Here we describe a novel superoxide-generating NADPH oxidase referred to as NADPH oxidase 5 (NOX5). NOX5 is distantly related to the gp91(phox) subunit of the phagocyte NADPH oxidase with conserved regions crucial for the electron transport (NADPH, FAD and heme binding sites). However, NOX5 has a unique N-terminal extension that contains three EF hand motifs. The mRNA of NOX5 is expressed in pachytene spermatocytes of testis and in B- and T-lymphocyte-rich areas of spleen and lymph nodes. When heterologously expressed, NOX5 was quiescent in unstimulated cells. However, in response to elevations of the cytosolic Ca(2+) concentration it generated large amounts of superoxide. Upon Ca(2+) activation, NOX5 also displayed a second function: it became a proton channel, presumably to compensate charge and pH alterations due to electron export. In summary, we have identified a novel NADPH oxidase that generates superoxide and functions as a H(+) channel in a Ca(2+)-dependent manner. NOX5 is likely to be involved in Ca(2+)-activated, redox-dependent processes of spermatozoa and lymphocytes such as sperm-oocyte fusion, cell proliferation, and cytokine secretion.
Keywords		Amino Acid Sequence — Animals — COS Cells — Calcium/ metabolism/physiology — Cytosol/metabolism — Electrophysiology — Genome — Hela Cells — Humans — In Situ Hybridization — Ion Transport — Lymph Nodes/ enzymology — Male — Membrane Proteins/genetics/ metabolism/physiology — Molecular Sequence Data — NADPH Oxidase/chemistry/genetics/ metabolism/physiology — Polymerase Chain Reaction — Protons — Sequence Homology, Amino Acid — Spleen/ enzymology — Superoxides/metabolism — Testis/ enzymology
Identifiers		DOI: 10.1074/jbc.M103034200 PMID: 11483596
Full text		Article - Limited access to UNIGE Other version: http://www.jbc.org/content/276/40/37594.full.pdf
Structures		Faculté de médecine / Section de médecine fondamentale / Département de pathologie et immunologie
Citation (ISO format)		BANFI, Botond et al. A Ca(2+)-activated NADPH oxidase in testis, spleen, and lymph nodes. In: Journal of Biological Chemistry, 2001, vol. 276, n° 40, p. 37594-37601. https://archive-ouverte.unige.ch/unige:11131