Novel p47 ^phox -Related Organizers Regulate Localized NADPH Oxidase 1 (Nox1) Activity

Abstract

The mechanisms that determine localized formation of reactive oxygen species (ROS) via NADPH oxidases (Nox) in nonphagocytic cells are unknown. We show that the c-Src substrate proteins Tks4 and Tks5 are functional members of a p47 phox -related organizer superfamily. Tks proteins selectively support Nox1 and Nox3 (vs. Nox2 and Nox4) activity in reconstituted cellular systems, and interact with the NoxA1 activator protein through an SH3-mediated interaction. Endogenous Tks4 is required for Rac GTPase-dependent ROS production by DLD1 colon cancer cells. Tks4 recruits Nox1 to invadopodia that form in DLD1 cells in a Tks-and Nox-dependent fashion. We propose that Tks organizers represent novel members of an organizer superfamily that link Nox to localized ROS formation.

Signaling inputs to invadopodia and podosomes

“…In this way, TKS5 might promote actin polymerization at nascent invadopodia (Oikawa et al, 2008;Stylli et al, 2009). TKS5 is also important for the generation of reactive oxygen species (ROS) Gianni et al, 2009), which might potentiate tyrosine kinase activity at invadopodia and podosomes by inhibiting tyrosine phosphatases Weaver, 2009). Additional potential effectors include Akt (Klippel et al, 1997;Yamaguchi et al, 2011), TIAM1 (Ceccarelli et al, 2007) and other PtdIns(3,4)P 2 -binding partners with unknown functions at invadopodia.…”

Membrane lipids in invadopodia and podosomes: Key structures for cancer invasion and metastasis

“…Both Tks5 and its relative, Tks4, have been shown to play important roles in podosome formation, matrix degradation, and tumor growth in vivo [80][81][82][83]. Recently, they have been shown to mediate the generation of reactive oxygen species (ROS) at the invadopodia of cancer cells, which is required for invadopodia formation and cancer cell invasion [84,85]. Moreover, Tks5 binds to supervillin, a lipid raft-enriched protein which is involved in integrin recycling, cell motility, and invadopodia formation [86][87][88], which suggests that they play roles as versatile regulators of invadopodia/podosomes.…”

FLT3-driven redox-modulation of Ezrin regulates leukaemic cell migration

“…Indeed the utilisation of ROS as signalling mediators in their own right has evolved to be tightly regulated spatially, temporally and in terms of substrate susceptibility. This regulation is facilitated by the discrete subcellular compartmentalisation of ROS production (Chen et al, 2009), the restricted availability of Nox activating and regulatory subunits (Gianni et al, 2009;Terada, 2006) and the presence of cytosolic scavenging and neutralising enzymes such as Cu/Zn SODs, GSH peroxidase (Terada, 2006) and Prxs (Rhee and Woo, 2011;Rhee et al, 2012) to prevent escape or accumulation of ROS to toxic levels. Substrate specificity is also regulated through co-localisation of ROS producing enzymes and the intended target of the oxidants produced, to distinct insulated intracellular compartments.…”

“…The recent identification and characterisation of two novel adaptor proteins for Nox1 and 3, Tks4 and Tks5 (Gianni et al, 2009), highlights the role of Nox regulatory molecules in dictating the specificity of the redox signalling and tailoring it to the physiological needs of the cell. The Tks proteins function in a similar manner to p47 phox, i.e.as organiser subunits controlling the recruitment of other subunits to the membrane, but appear to operate only within the invadopodia and podosomes of migrating cells, ensuring that Nox activation occurs within the confines of these actin-rich invading structures, which seem to require ROS for their stabilisation.…”