scholarly journals Peripheral Nerve Demyelination Caused by a Mutant Rho GTPase Guanine Nucleotide Exchange Factor, Frabin/FGD4

2007 ◽  
Vol 81 (1) ◽  
pp. 158-164 ◽  
Author(s):  
Claudia Stendel ◽  
Andreas Roos ◽  
Tine Deconinck ◽  
Jorge Pereira ◽  
François Castagner ◽  
...  
Keyword(s):  
Peripheral Nerve ◽  
Rho Gtpase ◽  
Guanine Nucleotide Exchange Factor ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Exchange Factor ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factor

scholarly journals Structure of the C-terminal guanine nucleotide exchange factor module of Trio in an autoinhibited conformation reveals its oncogenic potential

2019 ◽  
Vol 12 (569) ◽  
pp. eaav2449 ◽  
Author(s):  
Sumit J. Bandekar ◽  
Nadia Arang ◽  
Ena S. Tully ◽  
Brittany A. Tang ◽  
Brenna L. Barton ◽  
...  
Keyword(s):  
Rho Gtpase ◽  
Guanine Nucleotide Exchange Factor ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Ph Domain ◽  
Independent Manner ◽  
Exchange Factor ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factor ◽  
Factor Module

The C-terminal guanine nucleotide exchange factor (GEF) module of Trio (TrioC) transfers signals from the Gαq/11subfamily of heterotrimeric G proteins to the small guanosine triphosphatase (GTPase) RhoA, enabling Gαq/11-coupled G protein–coupled receptors (GPCRs) to control downstream events, such as cell motility and gene transcription. This conserved signal transduction axis is crucial for tumor growth in uveal melanoma. Previous studies indicate that the GEF activity of the TrioC module is autoinhibited, with release of autoinhibition upon Gαq/11binding. Here, we determined the crystal structure of TrioC in its basal state and found that the pleckstrin homology (PH) domain interacts with the Dbl homology (DH) domain in a manner that occludes the Rho GTPase binding site, thereby suggesting the molecular basis of TrioC autoinhibition. Biochemical and biophysical assays revealed that disruption of the autoinhibited conformation destabilized and activated the TrioC module in vitro. Last, mutations in the DH-PH interface found in patients with cancer activated TrioC and, in the context of full-length Trio, led to increased abundance of guanosine triphosphate–bound RhoA (RhoA·GTP) in human cells. These mutations increase mitogenic signaling through the RhoA axis and, therefore, may represent cancer drivers operating in a Gαq/11-independent manner.

scholarly journals Identification of a Novel Guanine Nucleotide Exchange Factor for the Rho GTPase

1996 ◽  
Vol 271 (41) ◽  
pp. 25452-25458 ◽  
Author(s):  
Matthew J. Hart ◽  
Sanju Sharma ◽  
Nadia elMasry ◽  
Rong-Guo Qiu ◽  
Peter McCabe ◽  
...  
Keyword(s):  
Rho Gtpase ◽  
Guanine Nucleotide Exchange Factor ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Exchange Factor ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factor

scholarly journals Vav3 collaborates with p190-BCR-ABL in lymphoid progenitor leukemogenesis, proliferation, and survival

Blood ◽  
2012 ◽  
Vol 120 (4) ◽  
pp. 800-811 ◽  
Author(s):  
Kyung Hee Chang ◽  
Abel Sanchez-Aguilera ◽  
Shuhong Shen ◽  
Amitava Sengupta ◽  
Malav N. Madhu ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Tyrosine Kinase ◽  
Rho Gtpase ◽  
Lymphoblastic Leukemia ◽  
Guanine Nucleotide Exchange Factor ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Exchange Factor ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factor

Despite the introduction of tyrosine kinase inhibitor therapy, the prognosis for p190-BCR-ABL+ acute lymphoblastic leukemia remains poor. In the present study, we present the cellular and molecular roles of the Rho GTPase guanine nucleotide exchange factor Vav in lymphoid leukemogenesis and explore the roles of Vav proteins in BCR-ABL–dependent signaling. We show that genetic deficiency of the guanine nucleotide exchange factor Vav3 delays leukemogenesis by p190-BCR-ABL and phenocopies the effect of Rac2 deficiency, a downstream effector of Vav3. Compensatory up-regulation of expression and activation of Vav3 in Vav1/Vav2–deficient B-cell progenitors increases the transformation ability of p190-BCR-ABL. Vav3 deficiency induces apoptosis of murine and human leukemic lymphoid progenitors, decreases the activation of Rho GTPase family members and p21-activated kinase, and is associated with increased Bad phosphorylation and up-regulation of Bax, Bak, and Bik. Finally, Vav3 activation only partly depends on ABL TK activity, and Vav3 deficiency collaborates with tyrosine kinase inhibitors to inhibit CrkL activation and impair leukemogenesis in vitro and in vivo. We conclude that Vav3 represents a novel specific molecular leukemic effector for multitarget therapy in p190-BCR-ABL–expressng acute lymphoblastic leukemia.

scholarly journals Combating Chagas Disease Through Inhibition of Tiam1, a Rho GTPase Guanine Nucleotide Exchange Factor

2016 ◽  
Author(s):  
Chirag Krishna ◽  
Li Xie ◽  
Philip Bourne ◽  
Celine DerMarderossian
Keyword(s):  
Chagas Disease ◽  
Latin American ◽  
Rho Gtpase ◽  
Guanine Nucleotide Exchange Factor ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Exchange Factor ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factor

Chagas disease is a major cardiovascular affliction primarily endemic to Latin American countries, affecting some ten to twelve million people worldwide. The currently available drugs, Benznidazole and Nifurtimox, are ineffective in the chronic stages and induce severe side effects. In an attempt to improve this situation we use an in silico drug repurposing strategy to correlate drug-protein interactions with positive clinical outcomes. The strategy involves a protein functional site similarity search, along with computational docking studies and, given the findings, a phosphatidylinositol (PIP) strip test to determine the activity of Posaconazole, a recently developed antifungal triazole, in conjunction with Tiam1, a Rho GTPase Guanine Nucleotide Exchange Factor. The results from both computational and in vitro studies indicate possible inhibition of phosphoinositides via Posaconazole, preventing Rho GTPase-induced proliferation of T. cruzi, the etiological agent of Chagas Disease.

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