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Mol Cell Proteomics. 2015 Apr;14(4):1064-78. doi: 10.1074/mcp.M114.043885. Epub 2015 Feb 14.

Proteomic analyses uncover a new function and mode of action for mouse homolog of Diaphanous 2 (mDia2).

Author information

1
From the ‡Division of Molecular Genetics, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands;
2
§Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, The Netherlands;
3
§Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, The Netherlands; ¶Netherlands Proteomics Centre and Cancer Genomics Centre, 3584 CH Utrecht, The Netherlands.
4
From the ‡Division of Molecular Genetics, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands; m.innocenti@nki.nl.

Abstract

mDia2 is an auto-inhibited Formin influencing actin dynamics upon conversion to the active conformation. mDia2 regulates actin-based protrusions and cell invasion, cell differentiation, vesicle trafficking, and cytokinesis. However, whether mDia2 has additional functions and how its action is functionally specified remain unknown. Here we draw the interactome of auto-inhibited and constitutively active mDia2 to address these issues. We embed mDia2 in protein networks accounting for its attributed functions and unexpectedly link it to the Ubiquitin Proteasome System. Taking FBXO3 as a test case, we show that mDia2 binds FBXO3 and p53, and regulates p53 transcriptional activity in an actin-nucleation-independent and conformation-insensitive manner. Increased mDia2 and FBXO3 levels elevate p53 activity and expression thereby sensitizing cells to p53-dependent apoptosis, whereas their decrease produces opposite effects. Thus, we discover a new role of mDia2 in p53 regulation suggesting that the closed conformation is biologically active and an FBXO3-based mechanism to functionally specify mDia2's activity.

PMID:
25682332
PMCID:
PMC4390252
DOI:
10.1074/mcp.M114.043885
[Indexed for MEDLINE]
Free PMC Article

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