Resumo

ARIAS, Andrés Augusto et al. Expression and activity of polymorphisms in the 67-kDa protein of the NADPH oxidase system. Biomédica [online]. 2004, vol.24, n.3, pp.262-272. ISSN 0120-4157.

The NADPH oxidase system plays a central role in the antimicrobial activity of phagocytes. This system is initiated by the translocation of cytosolic proteins p67 phox , p47 phox and p40 phox to be in close contact with membrane flavocytochrome b 558 . This event begins the electron transfer from cytosolic NADPH to molecular oxygen to produce superoxide anions. Herein, a functional analysis is presented of p67 phox polymorphisms identified from healthy humans. Mutations were generated in the p67 phox cDNA by site-directed mutagenesis and then transiently expressed in COS7 cells that also expressed gp91 phox , p22 phox , and p47 phox from stable transgenes. The changes Val166Ile, Pro329Ser and His389Gln correspond to possible polymorphisms identified in healthy individuals revealed a functional activity similar to COS phox cells transiently transfected with WT p67 phox ; therefore, these modifications are not associated with genetic deficiencies in NADPH oxidase. In conclusion, the COS phox system represents an easily transfectable model for analysis of NADPH oxidase function in intact cells. The analysis of mutant derivatives of p67 phox provides insight into molecular mechanisms by which this subunit regulates the NADPH oxidase.

Palavras-chave : NADPH oxidase; p67 phox; COS-phox cells; polymorphisms.

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