Disease relevance of CDC42

• Clostridium difficile toxin B, which inactivates Rho, Rac and Cdc42, markedly altered the distribution of peripheral actin filaments [1].

High impact information on CDC42

• In this study, we investigated the role of Rho family GTPases Cdc42 and Rho in shear stress-induced signal transduction and cytoskeleton reorganization [2].
• Dominant-negative mutants of Cdc42 and Rho, as well as recombinant C3 exoenzyme, attenuated the shear stress activation of c-Jun NH2-terminal kinases (JNKs), suggesting that Cdc42 and Rho regulate the shear stress induction of AP-1/TRE activity through JNKs [2].
• Our results showed that shear stress induced the translocation of Cdc42 and Rho from cytosol to membrane [2].
• Shear stress-induced cell alignment and stress fiber formation were inhibited by the dominant-negative mutants of Rho and p160ROCK, but not by the dominant-negative mutant of Cdc42, indicating that the Rho-p160ROCK pathway regulates the cytoskeletal reorganization in response to shear stress [2].
• IQGAP1, a Rac- and Cdc42-binding protein, directly binds and cross-links microfilaments [3].

Chemical compound and disease context of CDC42

• Neither Clostridium botulinum C3 toxin, which selectively ADP-ribosylates Rho, nor Clostridium sordellii lethal toxin, which inactivates Rac, affected cortical actin, suggesting that Cdc42 plays a specific role in the organization of subplasmalemmal actin [1].

Biological context of CDC42

• A novel fluorescence energy transfer assay to visualize Cdc42 activation in single cells shows that Cdc42 activity is polarized in the direction of flow [4].
• We propose that Cdc42 plays an active role in exocytosis by coupling the actin cytoskeleton to the sequential steps underlying membrane trafficking at the site of exocytosis [1].
• Rho family small GTPases (Rho, Rac, and Cdc42) play an important role in cell motility, adhesion, and cell division by signaling reorganization of the actin cytoskeleton [5].
• Finally, like Rac1, active Cdc42 induced transactivation of the cyclin D1 promoter cAMP response element binding protein/activating transcription factor-2 binding site [6].
• In this study we report that gamma-PAK, which is activated by the GTP-binding proteins Cdc42 and Rac, catalyses phosphorylation of intact non-muscle myosin II and isolated recombinant RLC. gamma-PAK phosphorylated endothelial cell myosin II to 0.85 +/- 0.02 mol PO4 per mol RLC [7].

Anatomical context of CDC42

• The levels of CDC42 and decorin mRNA were found to be higher in visceral adipose tissue than in subcutaneous adipose tissue in cattle, pig, and mice [8].
• Localized cdc42 activation, detected using a novel assay, mediates microtubule organizing center positioning in endothelial cells in response to fluid shear stress [4].
• Localized activation of Cdc42 as well as the activity of Par6 and protein kinase Czeta direct the reorientation of the MTOC to a position on the downstream side of the nucleus relative to the direction of flow [4].
• Here, we show that Cdc42 is activated by fluid shear stress and that activation is a consequence of integrins binding to extracellular matrix [4].
• Activated forms of the GTPases, Rac and Cdc42, are known to stimulate formation of microfilament-rich lamellipodia and filopodia, respectively, but the underlying mechanisms have remained obscure [3].

Associations of CDC42 with chemical compounds

• Thus, shear-stimulated integrin dynamics induce polarized Cdc42 activity, which induces MTOC localization through the Par6-protein kinase Czeta complex [4].
• Cloning and characterization of a novel Cdc42-associated tyrosine kinase, ACK-2, from bovine brain [9].
• By confocal immunofluorescence analysis, we found that Rac1 and Cdc42 are exclusively localized in the subplasmalemmal region in both resting and nicotine-stimulated cells [1].
• Also, Rac and Cdc42, but not Ras, were transglutaminated with lysine by DeltaDNT [10].
• Similar to Rac1-induced cyclin D1 expression, pretreatment with the antioxidants catalase and ebselen inhibited Cdc42-mediated transcription from the cyclin D1 promoter [6].

Other interactions of CDC42

• Fluid flow regulates morphology, physiology, and pathophysiology of vascular endothelial cells (reviewed in Ref. 1). The small GTPase Cdc42 mediates polarity in several systems including migrating cells and early embryos, which involve reorientation of the microtubule organizing center (MTOC) and Golgi apparatus toward the direction of movement [4].
• In bovine adrenal chromaffin cells, we found Rac1, but not Cdc42, to be rapidly and selectively activated by secretory stimuli using an assay selective for the activated GTPases [11].
• Cdc42-induced cyclin D1 promoter activation was independent of ERK as evidenced by insensitivity to PD-98059, an inhibitor of mitogen-activated protein kinase/ERK kinase (MEK) [6].
• Endogenous ILK was found to associate with PKL (paxillin kinase linker) and the Rac/Cdc42 guanine nucleotide exchange factor betaPIX [12].

References