Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

CDC42 binds PAK4 via an extended GTPase-effector interface.

ABSTRACT: The p21-activated kinase (PAK) group of serine/threonine kinases are downstream effectors of RHO GTPases and play important roles in regulation of the actin cytoskeleton, cell growth, survival, polarity, and development. Here we probe the interaction of the type II PAK, PAK4, with RHO GTPases. Using solution scattering we find that the full-length PAK4 heterodimer with CDC42 adopts primarily a compact organization. X-ray crystallography reveals the molecular nature of the interaction between PAK4 and CDC42 and shows that in addition to the canonical PAK4 CDC42/RAC interactive binding (CRIB) domain binding to CDC42 there are unexpected contacts involving the PAK4 kinase C-lobe, CDC42, and the PAK4 polybasic region. These additional interactions modulate kinase activity and increase the binding affinity of CDC42 for full-length PAK4 compared with the CRIB domain alone. We therefore show that the interaction of CDC42 with PAK4 can influence kinase activity in a previously unappreciated manner.

SUBMITTER: Ha BH

PROVIDER: S-EPMC5776996 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

CDC42 binds PAK4 via an extended GTPase-effector interface.

Ha Byung Hak BH Boggon Titus J TJ

Proceedings of the National Academy of Sciences of the United States of America 20180102 3

The p21-activated kinase (PAK) group of serine/threonine kinases are downstream effectors of RHO GTPases and play important roles in regulation of the actin cytoskeleton, cell growth, survival, polarity, and development. Here we probe the interaction of the type II PAK, PAK4, with RHO GTPases. Using solution scattering we find that the full-length PAK4 heterodimer with CDC42 adopts primarily a compact organization. X-ray crystallography reveals the molecular nature of the interaction between PAK ...[more]

PMID: 29295922

Similar Datasets

The Cdc42 Effector Kinase PAK4 Localizes to Cell-Cell Junctions and Contributes to Establishing Cell Polarity.

Project description:The serine/threonine kinase PAK4 is a Cdc42 effector whose role is not well understood; overexpression of PAK4 has been associated with some cancers, and there are reports that correlate kinase level with increased cell migration in vitro. Here we report that PAK4 is primarily associated with cell-cell junctions in all the cell lines we tested, and fails to accumulate at focal adhesions or at the leading edge of migrating cells. In U2OS osteosarcoma and MCF-7 breast cancer cell lines, PAK4 depletion did not affect collective cell migration, but affected cell polarization. By contrast, Cdc42 depletion (as reported by many studies) caused a strong defect in junctional assembly in multiple cells lines. We also report that the depletion of PAK4 protein or treatment of cells with the PAK4 inhibitor PF-3758309 can lead to defects in centrosome reorientation (polarization) after cell monolayer wounding. These experiments are consistent with PAK4 forming part of a conserved cell-cell junctional polarity Cdc42 complex. We also confirm β-catenin as a target for PAK4 in these cells. Treatment of cells with PF-3758309 caused inhibition of β-catenin Ser-675 phosphorylation, which is located predominantly at cell-cell junctions.

| S-EPMC4466050 | biostudies-literature

The Small GTPase Cdc42 Is a Major Regulator of Neutrophil Effector Functions.

Project description:Neutrophil granulocytes are key components of the innate immune system. As the first responders to inflammatory cues, they rapidly migrate toward the site of infection or inflammation and fulfill diverse effector functions. Since these effector functions can be both beneficial and harmful to the host and surrounding tissue, they require a strict control. The small GTPase Cdc42 is known to regulate neutrophil locomotion by controlling cytoskeleton rearrangement in murine neutrophils. However, the role of Cdc42 in other neutrophil functions in human neutrophils is still poorly understood. Here we demonstrate that in primary human neutrophils, Cdc42 controls directed and random migration, activation, and degranulation as well as the formation of reactive oxygen species, in a stimulus dependent manner. In addition, we show that Cdc42 regulates pathogen killing efficiency, both in murine and human neutrophils. Cdc42 regulation of neutrophil functions is linked to differential regulation of Akt, p38, and p42/44. Our data, therefore, suggests a mechanistic role for Cdc42 activity in primary human neutrophil biology, and identify Cdc42 activity as a target to modulate neutrophil effector mechanisms and killing efficacy.

| S-EPMC7304460 | biostudies-literature

Structure of Salmonella effector protein SopB N-terminal domain in complex with host Rho GTPase Cdc42.

Project description:SopB is a type III secreted Salmonella effector protein with phosphoinositide phosphatase activity and a distinct GTPase binding domain. The latter interacts with host Cdc42, an essential Rho GTPase that regulates critical events in eukaryotic cytoskeleton organization and membrane trafficking. Structural and biochemical analysis of the SopB GTPase binding domain in complex with Cdc42 shows for the first time that SopB structurally and functionally mimics a host guanine nucleotide dissociation inhibitor (GDI) by contacting key residues in the regulatory switch regions of Cdc42 and slowing Cdc42 nucleotide exchange.

| S-EPMC3339929 | biostudies-literature

Effector proteins exert an important influence on the signaling-active state of the small GTPase Cdc42.

Project description:GTP-binding (G) proteins regulate the flow of information in cellular signaling pathways by alternating between a GTP-bound "active" state and a GDP-bound "inactive" state. Cdc42, a member of the Rho family of Ras-related small G-proteins, plays key roles in the regulation of cell shape, motility, and growth. Here we describe the high resolution x-ray crystal structure for Cdc42 bound to the GTP analog guanylyl beta,gamma-methylene-diphosphonate (GMP-PCP) (i.e. the presumed signaling-active state) and show that it is virtually identical to the structures for the signaling-inactive, GDP-bound form of the protein, contrary to what has been reported for Ras and other G-proteins. Especially surprising was that the GMP-PCP- and GDP-bound forms of Cdc42 did not show detectable differences in their Switch I and Switch II loops. Fluorescence studies using a Cdc42 mutant in which a tryptophan residue was introduced at position 32 of Switch I also showed that there was little difference in the Switch I conformation between the GDP- and GMP-PCP-bound states (i.e. <10%), which again differed from Ras where much larger changes in Trp-32 fluorescence were observed when comparing these two nucleotide-bound states (>30%). However, the binding of an effector protein induced significant changes in the Trp-32 emission specifically from GMP-PCP-bound Cdc42, as well as in the phosphate resonances for GTP bound to this G-protein as indicated in NMR studies. An examination of the available structures for Cdc42 complexed to different effector proteins, versus the x-ray crystal structure for GMP-PCP-bound Cdc42, provides a possible explanation for how effectors can distinguish between the GTP- and GDP-bound forms of this G-protein and ensure that the necessary conformational changes for signal propagation occur.

| S-EPMC2376242 | biostudies-literature

The small Rho GTPase Cdc42 regulates neutrophil polarity via CD11b integrin signaling.

Project description:Neutrophil migration to sites of infection is the first line of cellular defense. A key event of migration is the maintenance of a polarized morphology, which is characterized by a single leading edge of filamentous actin and a contractile uropod devoid of filamentous actin protrusions. Using a mouse model of high Cdc42 activity, we previously demonstrated the importance of Cdc42 activity in neutrophil migration. However, the specific functions of Cdc42 in this process remain to be understood. Using neutrophils genetically deficient in Cdc42, we show that Cdc42 regulates directed migration by maintaining neutrophil polarity. Although it is known to be activated at the front, Cdc42 suppresses protrusions at the uropod. Interestingly, Cdc42 makes use of the integrin CD11b during this process. Cdc42 determines the redistribution of CD11b at the uropod. In turn, using CD11b-null cells and CD11b crosslinking experiments, we show that CD11b modulates myosin light chain phosphorylation to suppress lateral protrusions. Our results uncover a new mechanism in which Cdc42 regulates the uropod through CD11b signaling to maintain polarity in migrating neutrophils. It also reveals new functions for CD11b in neutrophil polarity.

| S-EPMC3403354 | biostudies-literature

Cyp33 binds AU-rich RNA motifs via an extended interface that competitively disrupts the gene repressive Cyp33-MLL1 interaction in vitro.

Project description:Cyp33 is an essential human cyclophilin prolyl isomerase that plays myriad roles in splicing and chromatin remodeling. In addition to a canonical cyclophilin (Cyp) domain, Cyp33 contains an RNA-recognition motif (RRM) domain, and RNA-binding triggers proline isomerase activity. One prominent role for Cyp33 is through a direct interaction with the mixed lineage leukemia protein 1 (MLL1, also known as KMT2A) complex, which is a histone methyltransferase that serves as a global regulator of human transcription. MLL activity is regulated by Cyp33, which isomerizes a key proline in the linker between the PHD3 and Bromo domains of MLL1, acting as a switch between gene activation and repression. The direct interaction between MLL1 and Cyp33 is critical, as deletion of the MLL1-PHD3 domain responsible for this interaction results in oncogenesis. The Cyp33 RRM is central to these activities, as it binds both the PHD3 domain and RNA. To better understand how RNA binding drives the action of Cyp33, we performed RNA-SELEX against full-length Cyp33 accompanied by deep sequencing. We have identified an enriched Cyp33 binding motif (AAUAAUAA) broadly represented in the cellular RNA pool as well as tightly binding RNA aptamers with affinities comparable and competitive with the Cyp33 MLL1-PHD3 interaction. RNA binding extends beyond the canonical RRM domain, but not to the Cyp domain, suggesting an indirect mechanism of interaction. NMR chemical shift mapping confirms an overlapping, but not identical, interface on Cyp33 for RNA and PHD3 binding. This finding suggests RNA can disrupt the gene repressive Cyp33-MLL1 complex providing another layer of regulation for chromatin remodeling by MLL1.

| S-EPMC7894885 | biostudies-literature

Regulation of Cdc42 polarization by the Rsr1 GTPase and Rga1, a Cdc42 GTPase-activating protein, in budding yeast.

Project description:Cdc42 plays a central role in establishing polarity in yeast and animals, yet how polarization of Cdc42 is achieved in response to spatial cues is poorly understood. Using live-cell imaging, we found distinct dynamics of Cdc42 polarization in haploid budding yeast in correlation with two temporal steps of the G1 phase. The position at which the Cdc42-GTP cluster develops changes rapidly around the division site during the first step but becomes stabilized in the second step, suggesting that an axis of polarized growth is determined in mid G1. Cdc42 polarization in the first step and its proper positioning depend on Rsr1 and its GTPase-activating protein (GAP) Bud2. Interestingly, Rga1, a Cdc42 GAP, exhibits transient localization to a site near the bud neck and to the division site during cytokinesis and G1, and this temporal change of Rga1 distribution is necessary for determination of a proper growth site. Mathematical modeling suggests that a proper axis of Cdc42 polarization in haploid cells might be established through a biphasic mechanism involving sequential positive feedback and transient negative feedback.

| S-EPMC4457026 | biostudies-literature

Cdc42 GTPase dynamics control directional growth responses.

Project description:Polarized cells reorient their direction of growth in response to environmental cues. In the fungus Candida albicans, the Rho-family small GTPase, Cdc42, is essential for polarized hyphal growth and Ca(2+) influx is required for the tropic responses of hyphae to environmental cues, but the regulatory link between these systems is unclear. In this study, the interaction between Ca(2+) influx and Cdc42 polarity-complex dynamics was investigated using hyphal galvanotropic and thigmotropic responses as reporter systems. During polarity establishment in an applied electric field, cathodal emergence of hyphae was lost when either of the two Cdc42 apical recycling pathways was disrupted by deletion of Rdi1, a guanine nucleotide dissociation inhibitor, or Bnr1, a formin, but was completely restored by extracellular Ca(2+). Loss of the Cdc42 GTPase activating proteins, Rga2 and Bem3, also abolished cathodal polarization, but this was not rescued by Ca(2+). Expression of GTP-locked Cdc42 reversed the polarity of hypha emergence from cathodal to anodal, an effect augmented by Ca(2+). The cathodal directional cue therefore requires Cdc42 GTP hydrolysis. Ca(2+) influx amplifies Cdc42-mediated directional growth signals, in part by augmenting Cdc42 apical trafficking. The Ca(2+)-binding EF-hand motif in Cdc24, the Cdc42 activator, was essential for growth in yeast cells but not in established hyphae. The Cdc24 EF-hand motif is therefore essential for polarity establishment but not for polarity maintenance.

| S-EPMC3896204 | biostudies-literature

Systems-wide analysis of K-Ras, Cdc42, and PAK4 signaling by quantitative phosphoproteomics.

Project description:Although K-Ras, Cdc42, and PAK4 signaling are commonly deregulated in cancer, only a few studies have sought to comprehensively examine the spectrum of phosphorylation-mediated signaling downstream of each of these key signaling nodes. In this study, we completed a label-free quantitative analysis of oncogenic K-Ras, activated Cdc42, and PAK4-mediated phosphorylation signaling, and report relative quantitation of 2152 phosphorylated peptides on 1062 proteins. We define the overlap in phosphopeptides regulated by K-Ras, Cdc42, and PAK4, and find that perturbation of these signaling components affects phosphoproteins associated with microtubule depolymerization, cytoskeletal organization, and the cell cycle. These findings provide a resource for future studies to characterize novel targets of oncogenic K-Ras signaling and validate biomarkers of PAK4 inhibition.

| S-EPMC3734570 | biostudies-literature

Gene expression profiles of Treg cells lacking Cdc42 GTPase

Project description:Treg cells play an important role in immune tolerance and tumor immune evasion through suppression of effector T cells. Treg cell lineage instability may be harnessed to trigger anti-tumor T cell immunity. However, the mechanism underlying Treg cell stability remains poorly understand. By characterizing Treg cell-specific heterozygous and homozygous Cdc42 knockout mice, we found that Cdc42 is essential for Treg cell stability. By RNA sequencing of heterozygous and homozygous Cdc42 knockout Treg cells, we found that Cdc42 maintains Treg cell stability through suppression of carbonic anhydrase I (CAI) expression.

2021-08-12 | GSE181779 | GEO

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data