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Updated: Aug 12, 2026

Bioluminescence Imaging of NADPH Oxidase Activity in Different Animal Models
Published on: October 22, 2012
Phagocyte NADPH oxidase p67-phox possesses a novel carboxylterminal binding site for the GTPases Rac2 and Cdc42
S L Faris1, L A Rinckel, J Huang
1Baltimore Veterans Affairs Medical Center and the Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland, 21201, USA.
Abstract:
Rac GTPases regulate activation of the phagocyte NADPH oxidase, a multi-component enzyme complex that produces superoxide in response to host infection. GTP-bound Rac binds to the cytosol protein p67-phox enabling it to participate in oxidase assembly. Details of this interaction are poorly understood. Previous studies showed that Rac/p67-phox binding is GTP-dependent and that several Rac1 mutants lost the ability to activate the oxidase even though they still bound p67-phox. Using two hybrid and blot overlay binding methods, we identified a novel binding site in the p67-phox C-terminus that binds Rac1, Rac2, and Cdc42, a related GTPase which does not activate the oxidase. Binding was independent of the GDP/GTP state. We also showed that GTP-Cdc42 binds p67-phox N-terminus similar to GTP-Rac. Therefore, Rac binding to p67-phox is not synonymous with NADPH oxidase activation, and Rac probably participates in other steps of oxidase activation in addition to binding p67-phox.
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