Gradients of Rac1 Nanoclusters Support Spatial Patterns of Rac1 Signaling

Remorino, Amanda; Beco, Simon de; Cayrac, Fanny; Federico, Fahima Di; Cornilleau, Gaetan; Gautreau, Alexis; Parrini, Maria Carla; Masson, Jean-Baptiste; Dahan, Maxime; Coppey, Mathieu

doi:10.1016/j.celrep.2017.10.069

Cited by 80 publications

(65 citation statements)

References 80 publications

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“…A similar mechanism has also been proposed for the formation of Rac1 nanoclusters, where the spatial regulation of Rac1 at the edges of lamellipodia is controlled by gradients of nanoclusters containing 50–100 molecules (Remorino et al, ). No such observation has yet been made for the related GTPase, RhoA, although both FRET‐biosensor imaging and computational studies have been employed to describe the complex spatial regulation of Rac1 and RhoA (Timpson et al, ; Johnsson et al, ).…”

Section: Potential Applications For Modelling Of Matrix Signallingmentioning

confidence: 99%

The extracellular matrix as a key regulator of intracellular signalling networks

Hastings

Skhinas

Fey

et al. 2018

British J Pharmacology

171

120

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The extracellular matrix (ECM) is a salient feature of all solid tissues within the body. This complex, acellular entity is composed of hundreds of individual molecules whose assembly, architecture and biomechanical properties are critical to controlling the behaviour and phenotype of the different cell types residing within tissues. Cells are the basic unit of life and the core building block of tissues and organs. At their simplest, they follow a set of rules, governed by their genetic code and effected through the complex protein signalling networks that these genes encode. These signalling networks assimilate and process the information received by the cell to control cellular decisions that govern cell fate. The ECM is the biggest provider of external stimuli to cells and as such is responsible for influencing intracellular signalling dynamics. In this review, we discuss the inclusion of ECM as a central regulatory signalling sub-network in computational models of cellular decision making, with a focus on its role in diseases such as cancer. LINKED ARTICLES: This article is part of a themed section on Translating the Matrix. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.1/issuetoc.

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Section: Potential Applications For Modelling Of Matrix Signallingmentioning

confidence: 99%

The extracellular matrix as a key regulator of intracellular signalling networks

Hastings

Skhinas

Fey

et al. 2018

British J Pharmacology

171

120

View full text Add to dashboard Cite

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“…An interesting possibility is that these smaller Rac1 nanoclusters are collected into larger, more stable assemblies of active Rac1 when confined by membrane ruffles. The formation of these larger assemblies could also be driven by, and indeed be dependent on, localized generation of PIP 3 (16), which we show here is a critical structural component of the smaller Rac1 nanocluster.…”

Section: Discussionmentioning

confidence: 62%

“…A similar integration of EM spatial mapping data with single-particle tracking data also suggests that Ras proteins may be transiently confined in immobile nanoclusters or diffuse freely (33,34). One important question is how these findings relate to Rac1 nanoclusters visualized by superresolution light microscopy, which shows that Rac1 nanoclusters have diameters of approximately 200 nm and contain up to 50 proteins (16). In contrast, the EM estimate of Rac1 nanocluster diameter is closer to 25 nm, and the L max values observed imply a stoichiometry of closer to five Rac1 proteins per cluster, predicated on the assumption that the clustering behavior of Rac1 broadly emulates that previously described for Ras (35).…”

Section: Discussionmentioning

confidence: 78%

Rac1 Nanoscale Organization on the Plasma Membrane Is Driven by Lipid Binding Specificity Encoded in the Membrane Anchor

Maxwell

Zhou

Hancock

2018

Molecular and Cellular Biology

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Rac1 is a small guanine-nucleotide binding protein that cycles between an inactive GDP-bound and active GTP-bound state to regulate cell motility and migration. Rac1 signaling is initiated from the plasma membrane (PM). Here we used high-resolution spatial mapping and manipulation of PM lipid composition to define Rac1 nanoscale organization. We found that Rac1 in the GTP- and GDP-bound states assemble into non-overlapping nanoclusters, thus Rac1 proteins undergo nucleotide-dependent segregation. Rac1 also selectively interacts with phosphatidic acid (PA) and phosphoinositol (3,4,5)-trisphosphate (PIP), resulting in nanoclusters enriched in these lipids. These lipids are structurally important because depleting the PM of PA or PIP impairs both Rac1 PM binding and Rac1 nanoclustering. Lipid binding specificity of Rac1 is encoded in the amino acid sequence of the polybasic domain (PBD) of the C-terminal membrane anchor. Point mutations within the PBD, including arginine to lysine substitutions, profoundly alter Rac1 lipid binding specificity without changing electrostatics of the protein, and result in impaired macropinocytosis and decreased cell spreading. We propose that Rac1 nanoclusters act as lipid based signaling platforms emulating the spatiotemporal organization of Ras proteins and show that the Rac1 PBD-prenyl anchor has a biological function that extends beyond simple electrostatic engagement with the PM.

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“…In eukaryotes, diverse Ras-family GTPases display heterogeneous diffusion on the plasma membrane, where active GTPases and other signaling proteins have been imaged in discrete subdiffraction limited ensembles, also referred to as nanoclusters (Murakoshi et al, 2004;Tian et al, 2007;Das et al, 2015;Nan et al, 2015;Zhou et al, 2015Zhou et al, , 2017Gronnier et al, 2017;Remorino et al, 2017). This is likely to reduce the diffusion of Cdc42 GTPase components locally.…”

Section: Discussionmentioning

confidence: 99%

Avidity‐driven polarity establishment via multivalent lipid– GTP ase module interactions

et al. 2018

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While Rho GTPases are indispensible regulators of cellular polarity, the mechanisms underlying their anisotropic activation at membranes have been elusive. Using the budding yeast Cdc42 GTPase module, which includes a guanine nucleotide exchange factor (GEF) Cdc24 and the scaffold Bem1, we find that avidity generated via multivalent anionic lipid interactions is a critical mechanistic constituent of polarity establishment. We identify basic cluster (BC) motifs in Bem1 that drive the interaction of the scaffold-GEF complex with anionic lipids at the cell pole. This interaction appears to influence lipid acyl chain ordering, thus regulating membrane rigidity and feedback between Cdc42 and the membrane environment. Sequential mutation of the Bem1 BC motifs, PX domain, and the PH domain of Cdc24 lead to a progressive loss of cellular polarity stemming from defective Cdc42 nanoclustering on the plasma membrane and perturbed signaling. Our work demonstrates the importance of avidity via multivalent anionic lipid interactions in the spatial control of GTPase activation.

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Gradients of Rac1 Nanoclusters Support Spatial Patterns of Rac1 Signaling

Cited by 80 publications

References 80 publications

The extracellular matrix as a key regulator of intracellular signalling networks

The extracellular matrix as a key regulator of intracellular signalling networks

Rac1 Nanoscale Organization on the Plasma Membrane Is Driven by Lipid Binding Specificity Encoded in the Membrane Anchor

Avidity‐driven polarity establishment via multivalent lipid– GTP ase module interactions

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