Daple is a novel non-receptor GEF required for trimeric G protein activation in Wnt signaling

Aznar, Nicolas; Midde, Krishna; Dunkel, Ying; López-Sánchez, Inmaculada; Pavlova, Yelena; Marivin, Arthur; Barbazán, Jorge; Murray, Fiona; Nitsche, Ulrich; Janssen, Klaus–Peter; Willert, Karl; Goel, Ajay; Abal, Miguel; Garcia‐Marcos, Mikel; Ghosh, Pradipta

doi:10.7554/elife.07091

Cited by 110 publications

(359 citation statements)

References 139 publications

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“…GEMs such as GIV or the synthetic KB-752 peptide are distinct from the other nonreceptor GEFs (such as Ric8A/B or AGS1) because they have a well-defined GBA motif (35) that can display a propensity for pleiotropy; i.e., the motif can either accelerate or inhibit nucleotide exchange and thereby serve as a GEF or a GDI, depending on the G-protein substrate and posttranslational modifications flanking the motif. Whether other GIV-related G-protein regulators, such as Daple (36) and Calnuc (35), which serve as GEFs for Gαi via GBA motifs that are similar to those in KB-752 and GIV, also serve as GDIs for Gαs remains to be explored.…”

Section: Discussionmentioning

confidence: 99%

GIV/Girdin activates Gαi and inhibits Gαs via the same motif

Gupta

Bhandari

Leyme

et al. 2016

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

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We previously showed that guanine nucleotide-binding (G) protein α subunit (Gα)-interacting vesicle-associated protein (GIV), a guanine-nucleotide exchange factor (GEF), transactivates Gα activity-inhibiting polypeptide 1 (Gαi) proteins in response to growth factors, such as EGF, using a short C-terminal motif. Subsequent work demonstrated that GIV also binds Gαs and that inactive Gαs promotes maturation of endosomes and shuts down mitogenic MAPK–ERK1/2 signals from endosomes. However, the mechanism and consequences of dual coupling of GIV to two G proteins, Gαi and Gαs, remained unknown. Here we report that GIV is a bifunctional modulator of G proteins; it serves as a guanine nucleotide dissociation inhibitor (GDI) for Gαs using the same motif that allows it to serve as a GEF for Gαi. Upon EGF stimulation, GIV modulates Gαi and Gαs sequentially: first, a key phosphomodification favors the assembly of GIV–Gαi complexes and activates GIV’s GEF function; then a second phosphomodification terminates GIV’s GEF function, triggers the assembly of GIV–Gαs complexes, and activates GIV’s GDI function. By comparing WT and GIV mutants, we demonstrate that GIV inhibits Gαs activity in cells responding to EGF. Consequently, the cAMP→PKA→cAMP response element-binding protein signaling axis is inhibited, the transit time of EGF receptor through early endosomes are accelerated, mitogenic MAPK–ERK1/2 signals are rapidly terminated, and proliferation is suppressed. These insights define a paradigm in G-protein signaling in which a pleiotropically acting modulator uses the same motif both to activate and to inhibit G proteins. Our findings also illuminate how such modulation of two opposing Gα proteins integrates downstream signals and cellular responses.

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Section: Discussionmentioning

confidence: 99%

GIV/Girdin activates Gαi and inhibits Gαs via the same motif

Gupta

Bhandari

Leyme

et al. 2016

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

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“…The β-catenin–independent Wnt pathway behaves as a double-edged sword; it suppresses tumorigenesis in normal epithelium and in early tumors, but also serves as a critical driver of epithelial-mesenchymal transition [EMT] and cancer invasion (17–27). We recently defined a novel paradigm in Wnt signaling in which Frizzled receptors (FZDs) activate the G proteins and trigger non-canonical Wnt signaling via Daple (CCDC88C), which is a Dishevelled (Dvl)-binding protein (28). Daple directly binds Wnt5a-activated FZDs, and serves as a guanine-nucleotide exchange factor (GEF) that activates the G protein, G αi (Fig.…”

Section: Introductionmentioning

confidence: 99%

Convergence of Wnt, growth factor, and heterotrimeric G protein signals on the guanine nucleotide exchange factor Daple

et al. 2018

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Cellular proliferation, differentiation, and morphogenesis are shaped by multiple signaling cascades; their concurrent dysregulation plays an integral role in cancer progression and is a common feature of many malignancies. Three such cascades that contribute to the oncogenic potential are those mediated by Wnt and Frizzled (FZD), growth factor receptor tyrosine kinases (RTKs), and trimeric G proteins and GPCRs. Daple is a Dishevelled (Dvl)- and FZD-binding protein and a guanine-nucleotide exchange factor (GEF) for the trimeric G protein, Gαi. Daple enhances β-catenin-independent Wnt signaling through its ability to activate the pathway downstream of the Wnt5/FZD7 pathway. Here we identified that Daple is a substrate of multiple RTKs and non-RTKs, and hence, a point of convergence for all three cascades. We show that phosphorylation by both RTKs and non-RTKs near the Dvl-binding motif in Daple dissociated Daple:Dvl complexes and augmented the ability of Daple to bind and activate Gαi which potentiated β-catenin-independent Wnt signals and triggered epithelial-mesenchymal transition (EMT) in a manner similar to that triggered by Wnt5A/FZD. Although Daple acts as a tumor suppressor in the healthy colon, but concurrent upregulation of Daple and epidermal growth factor receptor (EGFR) in colorectal tumors from patients was associated with poor prognosis. We conclude that Daple-dependent activation of Gαi and enhancement of β-catenin-independent Wnt signals is not just triggered by Wnt5a/FZD to suppress tumorigenesis, but also is hijacked by growth factor-RTKs to stoke tumor progression. Thus, this work defines a crosstalk paradigm amongst growth factor RTKs, trimeric G-proteins, and Wnt/FZD in cancer biology.

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“…These pathways regulate, for example, cell movement, cytoskeletal reorganization, and planar cell polarity-like signaling in mammalian systems. Accumulating mechanistic insight strengthens the concept that FZDs behave as bona fide G protein-coupled receptors (GPCRs) (Slusarski et al, 1997;Liu et al, 1999;Sheldahl et al, 1999;Ahumada et al, 2002;Katanaev et al, 2005;Katanaev and Buestorf, 2009;Kilander et al, 2011Kilander et al, , 2014aKoval and Katanaev, 2011;Halleskog et al, 2012;Aznar et al, 2015), whereas other aspects, such as G protein coupling selectivity, ligand-dependent functional selectivity, and the importance of G protein signaling downstream of FZDs, still remain obscure (Dijksterhuis et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

WNT Stimulation Dissociates a Frizzled 4 Inactive-State Complex with Gα_12/13

et al. 2016

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Frizzleds (FZDs) are unconventional G protein-coupled receptors that belong to the class Frizzled. They are bound and activated by the Wingless/Int-1 lipoglycoprotein (WNT) family of secreted lipoglycoproteins. To date, mechanisms of signal initiation and FZD-G protein coupling remain poorly understood. Previously, we showed that FZD 6 assembles with Ga i1 /Ga q (but not with Ga s , Ga o and Ga 12/13 ), and that these inactive-state complexes are dissociated by WNTs and regulated by the phosphoprotein Dishevelled (DVL). Here, we investigated the inactive-state assembly of heterotrimeric G proteins with FZD 4 , a receptor important in retinal vascular development and frequently mutated in Norrie disease or familial exudative vitreoretinopathy. Live-cell imaging experiments using fluorescence recovery after photobleaching show that human FZD 4 assembles-in a DVL-independent manner-with Ga 12/13 but not representatives of other heterotrimeric G protein subfamilies, such as Ga i1 , Ga o , Ga s , and Ga q . The FZD 4 -G protein complex dissociates upon stimulation with WNT-3A, WNT-5A, WNT-7A, and WNT-10B. In addition, WNT-induced dynamic mass redistribution changes in untransfected and, even more so, in FZD 4 green fluorescent protein-transfected cells depend on Ga 12/13 . Furthermore, expression of FZD 4 and Ga 12 or Ga 13 in human embryonic kidney 293 cells induces WNT-dependent membrane recruitment of p115-RHOGEF (RHO guanine nucleotide exchange factor, molecular weight 115 kDa), a direct target of Ga 12/13 signaling, underlining the functionality of an FZD 4 -Ga 12/13 -RHO signaling axis. In summary, Ga 12/13 -mediated WNT/FZD 4 signaling through p115-RHOGEF offers an intriguing and previously unappreciated mechanistic link of FZD 4 signaling to cytoskeletal rearrangements and RHO signaling with implications for the regulation of angiogenesis during embryonic and tumor development.

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Daple is a novel non-receptor GEF required for trimeric G protein activation in Wnt signaling

Cited by 110 publications

References 139 publications

GIV/Girdin activates Gαi and inhibits Gαs via the same motif

GIV/Girdin activates Gαi and inhibits Gαs via the same motif

Convergence of Wnt, growth factor, and heterotrimeric G protein signals on the guanine nucleotide exchange factor Daple

WNT Stimulation Dissociates a Frizzled 4 Inactive-State Complex with Gα_12/13

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Daple is a novel non-receptor GEF required for trimeric G protein activation in Wnt signaling

Cited by 110 publications

References 139 publications

GIV/Girdin activates Gαi and inhibits Gαs via the same motif

GIV/Girdin activates Gαi and inhibits Gαs via the same motif

Convergence of Wnt, growth factor, and heterotrimeric G protein signals on the guanine nucleotide exchange factor Daple

WNT Stimulation Dissociates a Frizzled 4 Inactive-State Complex with Gα12/13

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WNT Stimulation Dissociates a Frizzled 4 Inactive-State Complex with Gα_12/13