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bioRxiv · 10.1101/2022.02.14.480271

Daam1 negatively regulates USP10 activity

Phillips, A. T.·Boumil, E. F.·Venkatesan, A.·Castro, N.·Bernstein, A. M.
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Abstract

The differentiation of fibroblasts into pathological myofibroblasts during wound healing is in part characterized by increased cell surface expression of v-integrins. Our previous studies found that the deubiquitinase (DUB) USP10 removes ubiquitin from v-integrins, leading to cell surface integrin accumulation, subsequent TGF{beta}1 activation, and myofibroblast differentiation. In this study, a yeast-two hybrid screen elucidated a novel binding partner for USP10, the formin, Daam1. The USP10/Daam1 interaction was also supported by proximity ligation assay (PLA) activity. Treatment with TGF{beta}1 significantly increased USP10 and Daam1 protein expression, PLA signal, and co-localization to actin stress fibers. Furthermore, Daam1 siRNA knockdown significantly reduced a) co-precipitation of USP10 and Daam1 on purified actin stress fibers, and b) {beta}1- and {beta}5-integrin ubiquitination resulting in increased v-, {beta}1-, and {beta}5-integrin total protein levels, v integrin recycling to the cell surface, and extracellular fibronectin (FN) organization. Together, our data suggest that Daam1 negatively regulates USP10s DUB activity and subsequently maintains integrin protein homeostasis.

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Phillips, A. T., Boumil, E. F., Venkatesan, A., Castro, N., Bernstein, A. M.. 2022-02-14. Daam1 negatively regulates USP10 activity. https://doi.org/10.1101/2022.02.14.480271

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