The Rac Effector p67 phox Regulates Phagocyte NADPH Oxidase by Stimulating Vav1 Guanine Nucleotide Exchange Activity

Nucleotide Exchange Factor Vav1 Regulates The Hemopoietic Rho/Rac Guanine

Rac activation induces NADPH oxidase activity in transgenic COSphox cells, and the level of superoxide production is exchange factor-dependent.

Transient expression of constitutively active Rac1 derivatives, (G12V) or (Q61L), was sufficient to induce phagocyte NADPH oxidase activity in a COS-7 cell model in which human cDNAs for essential oxidase components, gp91(phox), p22(phox), p47(phox), and p67(phox), were expressed as stable transgenes. Expression of constitutively active Rac1 in "COS(phox)" cells induced translocation of p47(pho...

The hemopoietic Rho/Rac guanine nucleotide exchange factor Vav1 regulates N-formyl-methionyl-leucyl-phenylalanine-activated neutrophil functions.

Vav1 is a hemopoietic-specific Rho/Rac guanine nucleotide exchange factor that plays a prominent role in responses to multisubunit immune recognition receptors in lymphoid cells, but its contribution to regulation of neutrophil functions is unknown. Activated Rho family GTPases are critical participants in neutrophil signaling cascades initiated by binding of FMLP and other chemoattractants to ...

The domain organization of p67 phox, a protein required for activation of the superoxide-producing NADPH oxidase in phagocytes.

The phagocyte NADPH oxidase, crucial for innate immunity, is dormant in resting cells, but becomes activated during phagocytosis to produce superoxide, a precursor of microbicidal oxidants. In activation of the oxidase, the multidomain protein p67(phox)plays a central role: it translocates to the membrane as a ternary complex with p47(phox)and p40(phox), and interacts with the small GTPase Rac ...

The Rho/Rac-Family Guanine Nucleotide Exchange Factor VAV-1 Regulates Rhythmic Behaviors in C. elegans

Rhythmic behaviors are a fundamental feature of all organisms. Pharyngeal pumping, the defecation cycle, and gonadal-sheath-cell contractions are three well-characterized rhythmic behaviors in the nematode C. elegans. The periodicities of the rhythms range from subsecond (pharynx) to seconds (gonadal sheath) to minutes (defecation). However, the molecular mechanisms underlying these rhythmic be...