scholarly journals Spatial Organization of Rho GTPase signaling by RhoGEF/RhoGAP proteins

2018 ◽  
Author(s):  
Paul M. Müller ◽  
Juliane Rademacher ◽  
Richard D. Bagshaw ◽  
Keziban M. Alp ◽  
Girolamo Giudice ◽  
...  
Keyword(s):  
Rho Gtpases ◽  
Spatial Organization ◽  
Rho Gtpase ◽  
Critical Role ◽  
Control Cell ◽  
Positional Information ◽  
Small Gtpases ◽  
G Protein Coupled Receptors ◽  
Signaling Networks ◽  
G Protein Coupled

AbstractRho GTPases control cell morphogenesis and thus fundamental processes in all eukaryotes. They are regulated by 145 RhoGEF and RhoGAP multi-domain proteins in humans. How the Rho signaling system is organized to generate localized responses in cells and prevent their spreading is not understood. Here, we systematically characterized the substrate specificities, localization and interactome of the RhoGEFs/RhoGAPs and revealed their critical role in contextualizing and spatially delimiting Rho signaling. They localize to multiple compartments providing positional information, are extensively interconnected to jointly coordinate their signaling networks and are widely autoinhibited to remain sensitive to local activation. RhoGAPs exhibit lower substrate specificity than RhoGEFs and may contribute to preserving Rho activity gradients. Our approach led us to uncover a multi-RhoGEF complex downstream of G-protein-coupled receptors controlling a Cdc42/RhoA crosstalk. The spatial organization of Rho signaling thus differs from other small GTPases and expands the repertoire of mechanisms governing localized signaling activity.

scholarly journals Regulation of mTORC1 by Upstream Stimuli

Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 989
Author(s):  
Chase H. Melick ◽  
Jenna L. Jewell
Keyword(s):  
Amino Acids ◽  
Growth Factors ◽  
Control Cell ◽  
Mammalian Target Of Rapamycin ◽  
Small Gtpases ◽  
G Protein Coupled Receptors ◽  
Signaling Cascades ◽  
Growth Metabolism ◽  
Mtor Complex 1 ◽  
G Protein Coupled

The mammalian target of rapamycin (mTOR) is an evolutionary conserved Ser/Thr protein kinase that senses multiple upstream stimuli to control cell growth, metabolism, and autophagy. mTOR is the catalytic subunit of mTOR complex 1 (mTORC1). A significant amount of research has uncovered the signaling pathways regulated by mTORC1, and the involvement of these signaling cascades in human diseases like cancer, diabetes, and ageing. Here, we review advances in mTORC1 regulation by upstream stimuli. We specifically focus on how growth factors, amino acids, G-protein coupled receptors (GPCRs), phosphorylation, and small GTPases regulate mTORC1 activity and signaling.

scholarly journals Regulation of Rho GTPases in the Vasculature by Cullin3-Based E3 Ligase Complexes

2021 ◽  
Vol 9 ◽  
Author(s):  
Fabienne Podieh ◽  
Peter L. Hordijk
Keyword(s):  
Rho Gtpases ◽  
Vascular Function ◽  
Rho Gtpase ◽  
Current Knowledge ◽  
E3 Ligase ◽  
Small Gtpases ◽  
E3 Ligases ◽  
Cellular Processes ◽  
Ubiquitin E3 Ligase ◽  
Cytoskeletal Dynamics

Cullin3-based ubiquitin E3 ligases induce ubiquitination of substrates leading to their proteasomal or lysosomal degradation. BTB proteins serve as adaptors by binding to Cullin3 and recruiting substrate proteins, which enables specific recognition of a broad spectrum of targets. Hence, Cullin3 and its adaptors are involved in myriad cellular processes and organ functions. Cullin3-based ubiquitin E3 ligase complexes target small GTPases of the Rho subfamily, which are key regulators of cytoskeletal dynamics and cell adhesion. In this mini review, we discuss recent insights in Cullin3-mediated regulation of Rho GTPases and their impact on cellular function and disease. Intriguingly, upstream regulators of Rho GTPases are targeted by Cullin3 complexes as well. Thus, Rho GTPase signaling is regulated by Cullin3 on multiple levels. In addition, we address current knowledge of Cullin3 in regulating vascular function, focusing on its prominent role in endothelial barrier function, angiogenesis and the regulation of blood pressure.

Identification Methods of G Protein-Coupled Receptors

2011 ◽  
Vol 2 (4) ◽  
pp. 35-52
Author(s):  
Meriem Zekri ◽  
Karima Alem ◽  
Labiba Souici-Meslati
Keyword(s):  
Immune Responses ◽  
G Protein ◽  
Pharmaceutical Research ◽  
G Protein Coupled Receptors ◽  
Machine Learning Algorithms ◽  
Signaling Networks ◽  
Identification Methods ◽  
Physiological Processes ◽  
Cell Signaling Networks ◽  
G Protein Coupled

The G protein-coupled receptors (GPCRs) include one of the largest and most important families of multifunctional proteins known to molecular biology. They play a key role in cell signaling networks that regulate many physiological processes, such as vision, smell, taste, neurotransmission, secretion, immune responses, metabolism, and cell growth. These proteins are thus very important for understanding human physiology and they are involved in several diseases. Therefore, many efforts in pharmaceutical research are to understand their structures and functions, which is not an easy task, because although thousands GPCR sequences are known, many of them remain orphans. To remedy this, many methods have been developed using methods such as statistics, machine learning algorithms, and bio-inspired approaches. In this article, the authors review the approaches used to develop algorithms for classification GPCRs by trying to highlight the strengths and weaknesses of these different approaches and providing a comparison of their performances.

scholarly journals MicroRNA Regulation of the Small Rho GTPase Regulators—Complexities and Opportunities in Targeting Cancer Metastasis

Cancers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1092 ◽  
Author(s):  
Brock A. Humphries ◽  
Zhishan Wang ◽  
Chengfeng Yang
Keyword(s):  
Transcriptional Activation ◽  
Rho Gtpases ◽  
Cancer Metastasis ◽  
Rho Gtpase ◽  
Critical Role ◽  
Large Family ◽  
Actin Dynamics ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Guanine Nucleotide Exchange

The small Rho GTPases regulate important cellular processes that affect cancer metastasis, such as cell survival and proliferation, actin dynamics, adhesion, migration, invasion and transcriptional activation. The Rho GTPases function as molecular switches cycling between an active GTP-bound and inactive guanosine diphosphate (GDP)-bound conformation. It is known that Rho GTPase activities are mainly regulated by guanine nucleotide exchange factors (RhoGEFs), GTPase-activating proteins (RhoGAPs), GDP dissociation inhibitors (RhoGDIs) and guanine nucleotide exchange modifiers (GEMs). These Rho GTPase regulators are often dysregulated in cancer; however, the underlying mechanisms are not well understood. MicroRNAs (miRNAs), a large family of small non-coding RNAs that negatively regulate protein-coding gene expression, have been shown to play important roles in cancer metastasis. Recent studies showed that miRNAs are capable of directly targeting RhoGAPs, RhoGEFs, and RhoGDIs, and regulate the activities of Rho GTPases. This not only provides new evidence for the critical role of miRNA dysregulation in cancer metastasis, it also reveals novel mechanisms for Rho GTPase regulation. This review summarizes recent exciting findings showing that miRNAs play important roles in regulating Rho GTPase regulators (RhoGEFs, RhoGAPs, RhoGDIs), thus affecting Rho GTPase activities and cancer metastasis. The potential opportunities and challenges for targeting miRNAs and Rho GTPase regulators in treating cancer metastasis are also discussed. A comprehensive list of the currently validated miRNA-targeting of small Rho GTPase regulators is presented as a reference resource.

scholarly journals The metalloprotease Kuzbanian (ADAM10) mediates the transactivation of EGF receptor by G protein–coupled receptors

2002 ◽  
Vol 158 (2) ◽  
pp. 221-226 ◽  
Author(s):  
Yibing Yan ◽  
Kyoko Shirakabe ◽  
Zena Werb
Keyword(s):  
Signaling Pathways ◽  
G Protein ◽  
Egf Receptor ◽  
Critical Role ◽  
G Protein Coupled Receptors ◽  
Heparin Binding ◽  
Egf Receptors ◽  
Gpcr Activation ◽  
G Protein Coupled ◽  
Stimulation Of

Communication between different signaling pathways enables cells to coordinate the responses to diverse environmental signals. Activation of the transmembrane growth factor precursors plays a critical role in this communication and often involves metalloprotease-mediated proteolysis. Stimulation of G protein–coupled receptors (GPCR) transactivates the EGF receptors (EGFRs), which occurs via a metalloprotease-dependent cleavage of heparin-binding EGF (HB-EGF). However, the metalloprotease mediating the transactivation remains elusive. We show that the integral membrane metalloprotease Kuzbanian (KUZ; ADAM10), which controls Notch signaling in Drosophila, stimulates GPCR transactivation of EGFR. Upon stimulation of the bombesin receptors, KUZ increases the docking and activation of adaptors Src homology 2 domain–containing protein and Gab1 on the EGFR, and activation of Ras and Erk. In contrast, transfection of a protease domain–deleted KUZ, or blocking endogenous KUZ by morpholino antisense oligonucleotides, suppresses the transactivation. The effect of KUZ on shedding of HB-EGF and consequent transactivation of the EGFR depends on its metalloprotease activity. GPCR activation enhances the association of KUZ and its substrate HB-EGF with tetraspanin CD9. Thus, KUZ regulates the relay between the GPCR and EGFR signaling pathways.

scholarly journals Grit, a GTPase-Activating Protein for the Rho Family, Regulates Neurite Extension through Association with the TrkA Receptor and N-Shc and CrkL/Crk Adapter Molecules

2002 ◽  
Vol 22 (24) ◽  
pp. 8721-8734 ◽  
Author(s):  
Takeshi Nakamura ◽  
Misako Komiya ◽  
Kiyoaki Sone ◽  
Eiji Hirose ◽  
Noriko Gotoh ◽  
...  
Keyword(s):  
Tyrosine Kinases ◽  
Rho Gtpases ◽  
Rho Gtpase ◽  
Neuronal Cells ◽  
Small Gtpases ◽  
Actin Dynamics ◽  
Gtpase Activating Protein ◽  
Interacting Protein ◽  
High Affinity Receptor ◽  
Rho Family

ABSTRACT Neurotrophins are key regulators of the fate and shape of neuronal cells and act as guidance cues for growth cones by remodeling the actin cytoskeleton. Actin dynamics is controlled by Rho GTPases. We identified a novel Rho GTPase-activating protein (Grit) for Rho/Rac/Cdc42 small GTPases. Grit was abundant in neuronal cells and directly interacted with TrkA, a high-affinity receptor for nerve growth factor (NGF). Another pool of Grit was recruited to the activated receptor tyrosine kinase through its binding to N-Shc and CrkL/Crk, adapter molecules downstream of activated receptor tyrosine kinases. Overexpression of the TrkA-binding region of Grit inhibited NGF-induced neurite elongation. Further, we found some tendency for neurite promotion in full-length Grit-overexpressing PC12 cells upon NGF stimulation. These results suggest that Grit, a novel TrkA-interacting protein, regulates neurite outgrowth by modulating the Rho family of small GTPases.

scholarly journals Autotaxin, a Secreted Lysophospholipase D, Is Essential for Blood Vessel Formation during Development

2006 ◽  
Vol 26 (13) ◽  
pp. 5015-5022 ◽  
Author(s):  
Laurens A. van Meeteren ◽  
Paula Ruurs ◽  
Catelijne Stortelers ◽  
Peter Bouwman ◽  
Marga A. van Rooijen ◽  
...  
Keyword(s):  
Lysophosphatidic Acid ◽  
Critical Role ◽  
G Protein Coupled Receptors ◽  
Blood Vessel Formation ◽  
Lysophospholipase D ◽  
Motility Factor ◽  
Nucleotide Pyrophosphatase ◽  
G Protein Coupled ◽  
Deficient Mice

ABSTRACT Autotaxin (ATX), or nucleotide pyrophosphatase-phosphodiesterase 2, is a secreted lysophospholipase D that promotes cell migration, metastasis, and angiogenesis. ATX generates lysophosphatidic acid (LPA), a lipid mitogen and motility factor that acts on several G protein-coupled receptors. Here we report that ATX-deficient mice die at embryonic day 9.5 (E9.5) with profound vascular defects in yolk sac and embryo resembling the Gα13 knockout phenotype. Furthermore, at E8.5, ATX-deficient embryos showed allantois malformation, neural tube defects, and asymmetric headfolds. The onset of these abnormalities coincided with increased expression of ATX and LPA receptors in normal embryos. ATX heterozygous mice appear healthy but show half-normal ATX activity and plasma LPA levels. Our results reveal a critical role for ATX in vascular development, indicate that ATX is the major LPA-producing enzyme in vivo, and suggest that the vascular defects in ATX-deficient embryos may be explained by loss of LPA signaling through Gα13.

scholarly journals The critical role and potential target of the autotaxin/lysophosphatidate axis in pancreatic cancer

Tumor Biology ◽  
2017 ◽  
Vol 39 (3) ◽  
pp. 101042831769454 ◽  
Author(s):  
Ming Quan ◽  
Jiu-jie Cui ◽  
Xiao Feng ◽  
Qian Huang
Keyword(s):  
Pancreatic Cancer ◽  
Current Knowledge ◽  
Critical Role ◽  
Treatment Resistance ◽  
G Protein Coupled Receptors ◽  
Signaling Axis ◽  
Tumorigenesis And Progression ◽  
Pathologic Processes ◽  
G Protein Coupled

Autotaxin, an ecto-lysophospholipase D encoded by the human ENNP2 gene, is expressed in multiple tissues, and participates in numerous critical physiologic and pathologic processes including inflammation, pain, obesity, embryo development, and cancer via the generation of the bioactive lipid lysophosphatidate. Overwhelming evidences indicate that the autotaxin/lysophosphatidate signaling axis serves key roles in the numerous processes central to tumorigenesis and progression, including proliferation, survival, migration, invasion, metastasis, cancer stem cell, tumor microenvironment, and treatment resistance by interacting with a series of at least six G-protein-coupled receptors (LPAR1–6). This review provides an overview of the autotaxin/lysophosphatidate axis and collates current knowledge regarding its specific role in pancreatic cancer. With a deeper understanding of the critical role of the autotaxin/lysophosphatidate axis in pancreatic cancer, targeting autotaxin or lysophosphatidate receptor may be a potential and promising strategy for cancer therapy.

scholarly journals Multiple Sequence Elements Facilitate Chp Rho GTPase Subcellular Location, Membrane Association, and Transforming Activity

2006 ◽  
Vol 17 (7) ◽  
pp. 3108-3121 ◽  
Author(s):  
Emily J. Chenette ◽  
Natalia Y. Mitin ◽  
Channing J. Der
Keyword(s):  
Amino Acids ◽  
Rho Gtpases ◽  
Rho Gtpase ◽  
Subcellular Location ◽  
Small Gtpases ◽  
Membrane Association ◽  
Basic Amino Acids ◽  
Sequence Elements ◽  
Transforming Activity ◽  
Carboxy Terminal

Cdc42 homologous protein (Chp) is a member of the Rho family of small GTPases and shares significant sequence and functional similarity with Cdc42. However, unlike classical Rho GTPases, we recently found that Chp depends on palmitoylation, rather than prenylation, for association with cellular membranes. Because palmitoylation alone is typically not sufficient to promote membrane association, we evaluated the possibility that other carboxy-terminal residues facilitate Chp subcellular association with membranes. We found that Chp membrane association and transforming activity was dependent on the integrity of a stretch of basic amino acids in the carboxy terminus of Chp and that the basic amino acids were not simply part of a palmitoyl acyltransferase recognition motif. We also determined that the 11 carboxy-terminal residues alone were sufficient to promote Chp plasma and endomembrane association. Interestingly, stimulation with tumor necrosis factor-α activated only endomembrane-associated Chp. Finally, we found that Chp membrane association was not disrupted by Rho guanine nucleotide dissociation inhibitory proteins, which are negative regulators of Cdc42 membrane association and biological activity. In summary, the unique carboxy-terminal sequence elements that promote Chp subcellular location and function expand the complexity of mechanisms by which the cellular functions of Rho GTPases are regulated.

scholarly journals The Atypical Rho GTPase CHW-1 Works With SAX-3/Robo to Mediate Axon Guidance in Caenorhabditis elegans

2018 ◽  
Author(s):  
Jamie K. Alan ◽  
Sara Robinson ◽  
Katie Magsig ◽  
Rafael S. Demarco ◽  
Erik A. Lundquist
Keyword(s):  
Caenorhabditis Elegans ◽  
Axon Guidance ◽  
Motor Neurons ◽  
Rho Gtpases ◽  
Rho Gtpase ◽  
Genetic Interaction ◽  
Small Gtpases ◽  
Axon Pathfinding ◽  
Rho Proteins ◽  
C Elegans

AbstractDuring development, neuronal cells extend an axon towards their target destination in response to a cue to form a properly functioning nervous system. Rho proteins, Ras-related small GTPases that regulate cytoskeletal organization and dynamics, cell adhesion, and motility, are known to regulate axon guidance. Despite extensive knowledge about canonical Rho proteins (RhoA/Rac1/Cdc42), little is known about the Caenorhabditis elegans (C. elegans) atypical Cdc42-like family members CHW-1 and CRP-1 in regards to axon pathfinding and neuronal migration. chw-1(Chp/Wrch) encodes a protein that resembles human Chp (Wrch-2/RhoV) and Wrch-1 (RhoU), and crp-1 encodes for a protein that resembles TC10 and TCL. Here, we show that chw-1 works redundantly with crp-1 and cdc-42 in axon guidance. Furthermore, proper levels of chw-1 expression and activity are required for proper axon guidance. When examining CHW-1 GTPase mutants, we found that the native CHW-1 protein is likely partially activated, and mutations at a conserved residue (position 12 using Ras numbering, position 18 in CHW-1) alter axon guidance and neural migration. Additionally, we showed that chw-1 genetically interacts with the guidance receptor sax-3 in PDE neurons. Finally, in VD/DD motor neurons, chw-1 works downstream of sax-3 to control axon guidance. In summary, this is the first study implicating the atypical Rho GTPases chw-1 and crp-1 in axon guidance. Furthermore, this is the first evidence of genetic interaction between chw-1 and the guidance receptor sax-3. These data suggest that chw-1 is likely acting downstream and/or in parallel to sax-3 in axon guidance.

Sign in / Sign up

Export Citation Format

Share Document