Nck adaptor proteins link nephrin to the actin cytoskeleton of kidney podocytes

Jones, Nina; Blasutig, Ivan M.; Eremina, Vera; Ruston, Julie; Bladt, Friedhelm; Li, Hongping; Huang, Haiming; Larose, Louise; Li, Shawn S.‐C.; Takano, Tomoko; Quaggin, Susan E.; Pawson, Tony

doi:10.1038/nature04662

Cited by 428 publications

(555 citation statements)

References 30 publications

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“…Based on recent data, it appears that at least two major SD signaling pathways can be discerned: (i) acute, reversible phosphotyrosine-based ZO-1 (12) and nephrin (13,(42)(43)(44) signaling leading to P-nephrin-Nck-mediated actin reorganization (14,45). (ii) Chronic calcium (6, 7) and phosphoserine/ threonine signaling-mediated regulation of cytoskeleton dynam- ics and podocyte survival (29,46,47).…”

Section: Discussionmentioning

confidence: 99%

Nuclear relocation of the nephrin and CD2AP-binding protein dendrin promotes apoptosis of podocytes

Asanuma

Campbell

Kim

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

126

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Kidney podocytes and their slit diaphragms (SDs) form the final barrier to urinary protein loss. There is mounting evidence that SD proteins also participate in intracellular signaling pathways. The SD protein nephrin serves as a component of a signaling complex that directly links podocyte junctional integrity to actin cytoskeletal dynamics. Another SD protein, CD2-associated protein (CD2AP), is an adaptor molecule involved in podocyte homeostasis that can repress proapoptotic TGF-␤ signaling in podocytes. Here we show that dendrin, a protein originally identified in telencephalic dendrites, is a constituent of the SD complex, where it directly binds to nephrin and CD2AP. In experimental glomerulonephritis, dendrin relocates from the SD to the nucleus of injured podocytes. High-dose, proapoptotic TGF-␤1 directly promotes the nuclear import of dendrin, and nuclear dendrin enhances both staurosporine-and TGF-␤1-mediated apoptosis. In summary, our results identify dendrin as an SD protein with proapoptotic signaling properties that accumulates in the podocyte nucleus in response to glomerular injury and provides a molecular target to tackle proteinuric kidney diseases. Nuclear relocation of dendrin may provide a mechanism whereby changes in SD integrity could translate into alterations of podocyte survival under pathological conditions. glomerular injury ͉ proapoptotic signaling ͉ TGF-␤ signaling ͉ slit diaphragm G lomerular podocytes serve as the final barrier to urinary protein loss by the formation and maintenance of podocyte foot processes (FP) and the interposed slit diaphragm (SD) (1). All forms of nephrotic syndrome are characterized by abnormalities in podocytes, including retraction (effacement) of podocyte FP and/or molecular reorganization of the SD (1). The discovery of several podocyte proteins and their mutation analysis, including nephrin (2), CD2-associated protein (CD2AP) (3), ␣-actinin-4 (4), podocin (5), TRPC6 (6, 7), and neph1 (8), have shed light on the pathogenesis of proteinuria and emphasized the critical role of the podocyte and the SD in maintaining the function of the glomerular filtration barrier. At the cytoplasmic insertion site of the SD, ZO-1 (9), ␣-, ␤-, ␥-catenins (10), podocin (11), and CD2AP (3) are present. In nephrotic syndrome, the normal podocyte substructure is lost, with effacement of podocyte FP, proteinuria (1), as well as altered phosphorylation of ZO-1 (12) and nephrin (13,14).Dendrin is a proline-rich protein of unknown function that was originally identified in telencephalic dendrites of sleep-deprived rats (15). In the brain, two protein variants (81 kDa, 89 kDa) were identified in cytosolic and membranous protein fractions (15). More recently, KIBRA, a WW domain-containing protein, was identified as a dendrin-interacting protein, but the functional relevance of this interaction remains to be established (16). Here we show that dendrin is a component of the SD complex. We further show that dendrin relocates to the nucleus of injured podocytes in a murine model of cr...

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Section: Discussionmentioning

confidence: 99%

Nuclear relocation of the nephrin and CD2AP-binding protein dendrin promotes apoptosis of podocytes

Asanuma

Campbell

Kim

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

126

View full text Add to dashboard Cite

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“…Such signaling adapters often harbor multiple SH3 domains, each capable of binding a canonical polyproline motif (14). Genetic, cell biological, and biochemical evidence supports a role for the SH2/SH3 adapter protein Nck in the activation of N-WASP (15)(16)(17)(18)(19)(20)(21)(22). Phosphorylated tyrosine residues on membrane receptors, such as the podocyte adhesion receptor nephrin and the vaccinia virus membrane protein A36R, localize Nck to the plasma membrane through its SH2 domain.…”

mentioning

confidence: 99%

“…Phosphorylated tyrosine residues on membrane receptors, such as the podocyte adhesion receptor nephrin and the vaccinia virus membrane protein A36R, localize Nck to the plasma membrane through its SH2 domain. Nck then directly binds N-WASP and the N-WASPassociated protein WIP, leading to localized actin polymerization (15,20,21,23). Similar to Nck, Grb2 is an SH2/SH3 adapter that binds and activates N-WASP (24,25), acting in concert with Nck to promote actin-dependent vaccinia virus motility (26).…”

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confidence: 99%

Allosteric N-WASP activation by an inter-SH3 domain linker in Nck

Okrut

Prakash

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Actin filament networks assemble on cellular membranes in response to signals that locally activate neural Wiskott-Aldrich-syndrome protein (N-WASP) and the Arp2/3 complex. An inactive conformation of N-WASP is stabilized by intramolecular contacts between the GTPase binding domain (GBD) and the C helix of the verprolin-homology, connector-helix, acidic motif (VCA) segment. Multiple SH3 domaincontaining adapter proteins can bind and possibly activate N-WASP, but it remains unclear how such binding events relieve autoinhibition to unmask the VCA segment and activate the Arp2/3 complex. Here, we have used purified components to reconstitute a signaling cascade driven by membrane-localized Src homology 3 (SH3) adapters and N-WASP, resulting in the assembly of dynamic actin networks. Among six SH3 adapters tested, Nck was the most potent activator of N-WASP-driven actin assembly. We identify within Nck a previously unrecognized activation motif in a linker between the first two SH3 domains. This linker sequence, reminiscent of bacterial virulence factors, directly engages the N-WASP GBD and competes with VCA binding. Our results suggest that animals, like pathogenic bacteria, have evolved peptide motifs that allosterically activate N-WASP, leading to localized actin nucleation on cellular membranes.

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“…La liaison de la néphrine à son ligand entraîne un regroupement des complexes dans des microdomaines lipidiques (lipid rafts). Cet événement va activer la protéine Fyn, un membre de la famille Src kinase, qui phosphoryle plusieurs résidus tyrosine situés à l'extré-mité carboxy-terminale de la néphrine ; à ce niveau, des protéines kinases et des protéines adaptatrices sont recrutées qui se lient ensuite à la néphrine via leurs domaines SH2 [7][8][9][10]. La phosphorylation de la néphrine par Fyn a deux conséquences essentielles ( Figure 3) : (1) elle active la PI3K via l'interaction du domaine SH2 de la sous-unité régulatrice p85 de cette dernière avec le domaine cytoplasmique de la néphrine tandis que la sous-unité catalytique p110 génère des phosphoinositides capables de recruter et d'activer la sérine thréonine kinase Akt, qui joue un rôle clé dans les processus de survie du podocyte.…”

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“…Cette fente est fermée par une mince membrane, le diaphragme de fente, qui joue un rôle essentiel dans la perméabilité aux protéines de la barrière glomérulaire » (repris de l'encadré de Raymond Ardaillou, dans [20] phorylation de la néphrine provoque le détachement de la podocine et la liaison de la -arrestine-2 à la néphrine qui subit alors une endocytose suivie d'une dégradation, interrompant ainsi la voie de signalisation [11]. Outre son rôle sur l'activation de la néphrine, Fyn interagit avec N-WASP (Wiskott Aldrich syndrome protein) qu'elle phosphoryle, entraînant le recrutement et l'ancrage de NCK aux microdomaines lipidiques [7,8]. La famille des protéines adaptatrices Nck comprend Nck1 (Nck) et Nck2 (Nck ou GRB4).…”

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