Selectivity in subunit composition of Ena/VASP tetramers |
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Authors: | Daisy?N Riquelme Aaron?S Meyer Melanie Barzik Amy Keating Frank?B Gertler |
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Institution: | *The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute for Technology, Cambridge, MA 02139, U.S.A.;†Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, U.S.A.;§Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, U.S.A. |
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Abstract: | The members of the actin regulatory family of Ena/VASP proteins form stable tetramers. The vertebrate members of the Ena/VASP family, VASP, Mena and EVL, have many overlapping properties and expression patterns, but functional and regulatory differences between paralogues have been observed. The formation of mixed oligomers may serve a regulatory role to refine Ena/VASP activity. While it has been assumed that family members can form mixed oligomers, this possibility has not been investigated systematically. Using cells expressing controlled combinations of VASP, Mena and EVL, we evaluated the composition of Ena/VASP oligomers and found that VASP forms oligomers without apparent bias with itself, Mena or EVL. However, Mena and EVL showed only weak hetero-oligomerization, suggesting specificity in the association of Ena/VASP family members. Co-expression of VASP increased the ability of Mena and EVL to form mixed oligomers. Additionally, we found that the tetramerization domain (TD) at the C-termini of Ena/VASP proteins conferred the observed selectivity. Finally, we demonstrate that replacement of the TD with a synthetic tetramerizing coiled coil sequence supports homo-oligomerization and normal VASP subcellular localization. |
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Keywords: | actin Ena/VASP EVH2 EVL Mena oligomerization VASP |
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