Jpn. J. Infect. Dis., 57, S22-S23, 2004
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Mechanisms of Activation of NADPH Oxidases
Robert A. Clark*, Terry Kay Epperson and Anthony J. Valente
Department of Medicine, University of Texas Health Science
Center, South Texas Veterans Health Care System, San Antonio,
Texas, USA
*Corresponding author: clarkra@uthscsa.edu
SUMMARY: The members of the NOX family of enzymes are expressed
in a variety of tissues and serve a number of functions. There
is a high level of conservation of primary protein sequence, as
well as functional features, although specialized responses are
beginning to emerge. In this context, our data demonstrate that
the NOX1 cytoplasmic domains interact efficiently with the cytoplasmic
subunits of the phagocyte NADPH oxidase and identify the second
cytoplasmic loop of NOX electron transporters as a crucial domain
for enzyme function. Studies of cytosolic co-factors showed that
the C-terminal cytoplasmic domain of NOX1 was absolutely required
for activation with NOXO1 and NOXA1 and that this activity required
interaction of the putative NADPH-binding region of this domain
with NOXA1. Finally, we have provided the first example of how
alternative splicing of a NOX co-factor may be involved in the
regulation of NADPH oxidase function.