Regulation of Cdc42 and its effectors in epithelial morphogenesis

Pichaud, Franck; Walther, Rhian F.; Almeida, Francisca Nunes de

doi:10.1242/jcs.217869

Cited by 102 publications

(83 citation statements)

References 165 publications

(208 reference statements)

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“…Cell morphogenesis, proliferation, and differentiation all critically rely on polarized molecular cues. In metazoans and fungi, the Rho family guanosine triphosphatase (GTPase) Cdc42 is central for regulation of polarized cortical processes [1][2][3]. Cdc42 associates with the plasma membrane through a prenylated cysteine at the C-terminal CAAX motif and alternates between the active, guanosine triphosphate (GTP)-bound and the inactive, guanosine diphosphate (GDP)-bound state.…”

Section: Introductionmentioning

confidence: 99%

Optogenetics reveals Cdc42 local activation by scaffold-mediated positive feedback and Ras GTPase

et al. 2020

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Local activity of the small GTPase Cdc42 is critical for cell polarization. Whereas scaffoldmediated positive feedback was proposed to break symmetry of budding yeast cells and produce a single zone of Cdc42 activity, the existence of similar regulation has not been probed in other organisms. Here, we address this problem using rod-shaped cells of fission yeast Schizosaccharomyces pombe, which exhibit zones of active Cdc42-GTP at both cell poles. We implemented the CRY2-CIB1 optogenetic system for acute light-dependent protein recruitment to the plasma membrane, which allowed to directly demonstrate positive feedback. Indeed, optogenetic recruitment of constitutively active Cdc42 leads to co-recruitment of the guanine nucleotide exchange factor (GEF) Scd1 and endogenous Cdc42, in a manner dependent on the scaffold protein Scd2. We show that Scd2 function is dispensable when the positive feedback operates through an engineered interaction between the GEF and a Cdc42 effector, the p21-activated kinase 1 (Pak1). Remarkably, this rewired positive feedback confers viability and allows cells to form 2 zones of active Cdc42 even when otherwise essential Cdc42 activators are lacking. These cells further revealed that the small GTPase Ras1 plays a role in both localizing the GEF Scd1 and promoting its activity, which potentiates the positive feedback. We conclude that scaffold-mediated positive feedback, gated by Ras activity, confers robust polarization for rod-shape formation.

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Section: Introductionmentioning

confidence: 99%

Optogenetics reveals Cdc42 local activation by scaffold-mediated positive feedback and Ras GTPase

et al. 2020

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“…Furthermore, β1 integrin null mice exhibit perturbed EC polarity coupled with redistribution of junctional molecules, including CD99 [42]. Indeed, CDC42 activity modulates numerous cellular pathways in response to diverse stimuli [15,43] and the ability of CD99 to modulate CDC42 activity suggests that CD99 will similarly regulate multiple events. CDC42 has well documented roles in angiogenesis and endothelial cell function and the increased angiogenic activity of EC we observed upon CD99 depletion is likely to be a combination of CDC42-mediated actin remodelling coupled with additional CDC42 regulated pathways known to impact on angiogenesis [16][17][18]20,[32][33][34].…”

Section: Discussionmentioning

confidence: 99%

CD99 regulates cancer cell transendothelial migration and endothelial cell function via CDC42 and actin remodelling

Mannion

Odell

Taylor

et al. 2019

Preprint

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BackgroundNinety percent of cancer deaths are attributable to metastatic progression [1]. Key steps in the metastatic cascade include the interactions occurring between the disseminating, metastatic cancer cells and the endothelium [1]. Migrating cancer cells intravasate in order to gain access to the lymphatic and haematogenous vasculature [2] and circulating cancer cells which survive anoikis, exposure to shear flow and immune surveillance, travel to distant sites where they extravasate into secondary tissues [1]. Adhesion, intravasation and extravasation all require intimate interactions between cancer cells and endothelial cells (EC), with both cell types contributing to transendothelial migration (TEM) [3]. Leukocytes undergo TEM when extravasating from blood to infected tissues as part of the inflammatory process and this mechanism provides a model for how cancer cell TEM might operate during metastasis [4,5].The type 1 transmembrane receptor CD99 is expressed in a variety of tissues including haematopoietic lineage cells and EC [6]. Amongst its reported functions, CD99 regulates the adhesion and TEM of haematopoietic cells [7,8]. In the endothelium, CD99 resides at the EC borders in a complex with ezrin, soluble adenylyl cyclase (sAC) and protein kinase A (PKA) (ref. 9). Endothelial cell CD99 is also localised within the lateral border recycling complex (LBRC), an intracellular compartment contiguous with the plasma membrane and located proximal to endothelial cell-cell junctions [9,10]. During TEM, CD99 undergoes homophilic interactions between the leukocyte and endothelium which facilitates the movement of the leukocyte between the EC junctions [7,9]. This engagement of endothelial CD99 triggers sAC, which activates PKA and enables the rapid turnover of CD99 from the LBRC to the endothelial cell junction to facilitate transmigration [9]. Although well established in leucocyte TEM, the involvement of CD99 in cancer progression remains enigmatic [11]. It is highly expressed in several haematopoietic malignancies as well as solid tumours, in particular in Ewing's sarcoma where lower CD99 expression results in reduced migration, tumour growth and metastasis [12,13]. However, in other cancers (such as osteosarcoma and gastric cancer), decreased CD99 expression is associated with tumour progression [11].

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“…For 7 instance, the apical domains of hepatocytes form bile canaliculi and are sites for polarised 8 delivery of bile salt and lipid transporters, whereas the baso-lateral domains of hepatocytes 9 are exposed to blood for insulin signalling and nutrient (glucose and lipid) uptake (Najjar and Several conserved proteins are essential for apico-basal polarity. Cdc42, a member of the Rho 20 family of small GTPases, controls polarised growth in yeast and mammalian epithelial cells 21 via the organisation of cytoskeletal and vesicular trafficking proteins (Pichaud, et al, 2019;22 Campanale, et al, 2017;Chiou, et al, 2017). The anterior PAR protein complex 23 (PAR3/PAR6/aPKC) interacts with Cdc42 and additional polarity factors that regulate cell 24 junctions and physically define the apico-basal axis in multiple cell types (Peglion and 25 Accordingly, distinct ER-PM contacts with different physical attributes and functions may 1 specify apical domain formation during epithelial cell development.…”

Section: Introductionmentioning

confidence: 99%

ER-PM contacts regulate apical domain formation in hepatocytes

Chung

Burden

Lorvellec

et al. 2020

Preprint

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1Apico-basal membrane polarity is fundamental for epithelial cell development and function. 2 Polarity factors including the small GTPase Cdc42, the Par3/Par6/aPKC complex, and 3 cytoskeletal proteins are recruited by the anionic lipids phosphatidylinositol 4,5-bisphosphate 4 and phosphatidylserine. But how these lipids accumulate at polarised sites remains unclear. 5We have examined roles of contacts between the endoplasmic reticulum and plasma 6 membrane (ER-PM contacts) in generating lipid gradients during apical domain formation. 7Comprehensive electron microscopy analyses in hepatocytes and epithelial spheroids 8 revealed two distinct ER-PM contact architectures that are spatially linked to apical and baso-9 lateral domains. Moreover, apical domain formation was delayed in HepG2 cells upon 10 modulating the ER-PM contact proteins E-Syt1 and ORP5. We propose ER-PM contacts 11 regulate apico-basal polarity via the lipid transfer proteins E-Syt1 and ORP5. Importantly, 12 our findings suggest that the spatial organisation of ER-PM contacts is a conserved feature of 13 polarised epithelial cells. 14 14Lipid transfer proteins (LTPs) that function at ER-PM contacts have been proposed to 15 regulate PI(4,5)P2 and PS homeostasis. For instance, the extended synaptotagmin protein 1 16 (E-Syt1) has been implicated in PI(4,5)P2 replenishment at the PM following intense 17 phospholipase C-mediated signalling events (Chang, et al., 2013). However, a clear role for 18 E-Syt1 in PI(4,5)P2 synthesis has not been elucidated and is even controversial (Saheki, et al., 19 2016). In addition, the oxysterol-binding protein related protein 5 (ORP5) has been shown to 20 deliver PS from the ER to the PM in exchange for phosphatidylinositol 4-phosphate (PI4P) at 21 ER-PM contacts (Sohn, et al., 2016; Chung, et al., 2015). Because PI4P is the precursor for 22 PI(4,5)P2 synthesis, ORP5 PS/PI4P exchange activity also modulates PI(4,5)P2 levels at the 23 PM (Sohn, et al., 2018). Hence, we hypothesised that distinct LTP activities at different ER-24 PM contacts may fine-tune the levels and localisation of PS and PI(4,5)P2 at the PM. 25

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Regulation of Cdc42 and its effectors in epithelial morphogenesis

Cited by 102 publications

References 165 publications

Optogenetics reveals Cdc42 local activation by scaffold-mediated positive feedback and Ras GTPase

Optogenetics reveals Cdc42 local activation by scaffold-mediated positive feedback and Ras GTPase

CD99 regulates cancer cell transendothelial migration and endothelial cell function via CDC42 and actin remodelling

ER-PM contacts regulate apical domain formation in hepatocytes

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