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All Dact (Dapper/Frodo) scaffold proteins dimerize and exhibit conserved interactions with Vangl, Dvl, and serine/threonine kinases.

Kivimäe S, Yang XY, Cheyette BN - BMC Biochem. (2011)

Bottom Line: We also found weaker, though conserved, interactions of all three Dact paralogs with the catenin superfamily member p120ctn.Combined with published functional evidence from targeted knock-out mice, these data support a conserved role for Dact proteins in kinase-regulated biochemistry involving Vangl and Dvl.This strongly suggests that a principal role for all Dact family members is in the PCP pathway or a molecularly related signaling cascade in vertebrates.

View Article: PubMed Central - HTML - PubMed

Affiliation: The Nina Ireland Laboratory of Developmental Neurobiology, Department of Psychiatry, University of California San Francisco, 1550 4th St, San Francisco CA 94158-2324, USA. bc@ucsf.edu

ABSTRACT

Background: The Dact family of scaffold proteins was discovered by virtue of binding to Dvl proteins central to Wnt and Planar Cell Polarity (PCP) signaling. Subsequently Dact proteins have been linked to a growing list of potential partners implicated in β-catenin-dependent and β-catenin-independent forms of Wnt and other signaling. To clarify conserved and non-conserved roles for this protein family, we systematically compared molecular interactions of all three murine Dact paralogs by co-immunoprecipitation of proteins recombinantly expressed in cultured human embryonic kidney cells.

Results: Every Dact paralog readily formed complexes with the Vangl, Dvl, and CK1δ/ε proteins of species ranging from fruit flies to humans, as well as with PKA and PKC. Dact proteins also formed complexes with themselves and with each other; their conserved N-terminal leucine-zipper domains, which have no known binding partners, were necessary and sufficient for this interaction, suggesting that it reflects leucine-zipper-mediated homo- and hetero-dimerization. We also found weaker, though conserved, interactions of all three Dact paralogs with the catenin superfamily member p120ctn. Complex formation with other previously proposed partners including most other catenins, GSK3, LEF/TCF, HDAC1, and TGFβ receptors was paralog-specific, comparatively weak, and/or more sensitive to empirical conditions.

Conclusions: Combined with published functional evidence from targeted knock-out mice, these data support a conserved role for Dact proteins in kinase-regulated biochemistry involving Vangl and Dvl. This strongly suggests that a principal role for all Dact family members is in the PCP pathway or a molecularly related signaling cascade in vertebrates.

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Dact2 coIPs with LEF/TCF family members; Dact1 & 2 coIP with HDAC1. A, LEF1. B, TCF1/TCF7. C, TCF3. D, TCF4. E, HDAC1: left 4 lanes murine, right two lanes human: 1S = human Dact1 short isoform, 1L = human Dact1 long form.
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Figure 6: Dact2 coIPs with LEF/TCF family members; Dact1 & 2 coIP with HDAC1. A, LEF1. B, TCF1/TCF7. C, TCF3. D, TCF4. E, HDAC1: left 4 lanes murine, right two lanes human: 1S = human Dact1 short isoform, 1L = human Dact1 long form.

Mentions: The Dact1 homologs from X. laevis and H. sapiens have been reported to form complexes with a subset of the LEF/TCF transcription factors that act as transcriptional regulators downstream of Wnt/β-catenin signaling and some other pathways [2,7,10]. We sought to replicate this finding and to test its specificity for Dact1 versus the other two Dact paralogs. Using the 293T cell line, we detected a positive coIP only for murine Dact2; this interaction was positive across all members of the LEF/TCF family examined (Figure 6A-D).


All Dact (Dapper/Frodo) scaffold proteins dimerize and exhibit conserved interactions with Vangl, Dvl, and serine/threonine kinases.

Kivimäe S, Yang XY, Cheyette BN - BMC Biochem. (2011)

Dact2 coIPs with LEF/TCF family members; Dact1 & 2 coIP with HDAC1. A, LEF1. B, TCF1/TCF7. C, TCF3. D, TCF4. E, HDAC1: left 4 lanes murine, right two lanes human: 1S = human Dact1 short isoform, 1L = human Dact1 long form.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3141656&req=5

Figure 6: Dact2 coIPs with LEF/TCF family members; Dact1 & 2 coIP with HDAC1. A, LEF1. B, TCF1/TCF7. C, TCF3. D, TCF4. E, HDAC1: left 4 lanes murine, right two lanes human: 1S = human Dact1 short isoform, 1L = human Dact1 long form.
Mentions: The Dact1 homologs from X. laevis and H. sapiens have been reported to form complexes with a subset of the LEF/TCF transcription factors that act as transcriptional regulators downstream of Wnt/β-catenin signaling and some other pathways [2,7,10]. We sought to replicate this finding and to test its specificity for Dact1 versus the other two Dact paralogs. Using the 293T cell line, we detected a positive coIP only for murine Dact2; this interaction was positive across all members of the LEF/TCF family examined (Figure 6A-D).

Bottom Line: We also found weaker, though conserved, interactions of all three Dact paralogs with the catenin superfamily member p120ctn.Combined with published functional evidence from targeted knock-out mice, these data support a conserved role for Dact proteins in kinase-regulated biochemistry involving Vangl and Dvl.This strongly suggests that a principal role for all Dact family members is in the PCP pathway or a molecularly related signaling cascade in vertebrates.

View Article: PubMed Central - HTML - PubMed

Affiliation: The Nina Ireland Laboratory of Developmental Neurobiology, Department of Psychiatry, University of California San Francisco, 1550 4th St, San Francisco CA 94158-2324, USA. bc@ucsf.edu

ABSTRACT

Background: The Dact family of scaffold proteins was discovered by virtue of binding to Dvl proteins central to Wnt and Planar Cell Polarity (PCP) signaling. Subsequently Dact proteins have been linked to a growing list of potential partners implicated in β-catenin-dependent and β-catenin-independent forms of Wnt and other signaling. To clarify conserved and non-conserved roles for this protein family, we systematically compared molecular interactions of all three murine Dact paralogs by co-immunoprecipitation of proteins recombinantly expressed in cultured human embryonic kidney cells.

Results: Every Dact paralog readily formed complexes with the Vangl, Dvl, and CK1δ/ε proteins of species ranging from fruit flies to humans, as well as with PKA and PKC. Dact proteins also formed complexes with themselves and with each other; their conserved N-terminal leucine-zipper domains, which have no known binding partners, were necessary and sufficient for this interaction, suggesting that it reflects leucine-zipper-mediated homo- and hetero-dimerization. We also found weaker, though conserved, interactions of all three Dact paralogs with the catenin superfamily member p120ctn. Complex formation with other previously proposed partners including most other catenins, GSK3, LEF/TCF, HDAC1, and TGFβ receptors was paralog-specific, comparatively weak, and/or more sensitive to empirical conditions.

Conclusions: Combined with published functional evidence from targeted knock-out mice, these data support a conserved role for Dact proteins in kinase-regulated biochemistry involving Vangl and Dvl. This strongly suggests that a principal role for all Dact family members is in the PCP pathway or a molecularly related signaling cascade in vertebrates.

Show MeSH