Formiineilla on alfa solenoidi rakenne. . Miten formiinit toimivat proteosomaalissa kartassa? ESIM: formiini DAAM1 ja DUB, deubikitinaasi USP10 sarveiskalvossa ?

 https://www.sciencedirect.com/science/article/pii/S0171933523000626

Highlights

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  We have elucidated a novel interaction between the formin, DAAM1 and the deubiquitinase, USP10.
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  DAAM1 binds to and inhibits USP10’s DUB activity through the FH2 domain of DAAM1 independent of its actin functions.
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  DAAM1 inhibition of USP10’s DUB activity subsequently affects integrin protein levels and integrin and matrix cell surface recycling.
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  The USP10/DAAM1 axis regulates integrin homeostasis that is important for a myriad of cellular processes.

 

  Formiini DAAM1 on   deubikitinaasin USP10 negatiivinen  regulaattori, siis tekee antifibroottisen vasteen esim sarveiskalvoa arpeuttavassa prosessissa estäen  fibroosia. 

Abstract

The differentiation of fibroblasts into pathological myofibroblasts during wound healing is characterized by increased cell surface expression of αv-integrins. Our previous studies found that the deubiquitinase (DUB) USP10 removes ubiquitin from αv-integrins, leading to cell surface integrin accumulation, subsequent TGFβ1 activation, and pathological myofibroblast differentiation. In this study, a yeast two-hybrid screen revealed a novel binding partner for USP10, the formin, DAAM1. We found that DAAM1 binds to and inhibits USP10’s DUB activity through the FH2 domain of DAAM1 independent of its actin functions. The USP10/DAAM1 interaction was also supported by proximity ligation assay (PLA) in primary human corneal fibroblasts. Treatment with TGFβ1 significantly increased USP10 and DAAM1 protein expression, PLA signal, and co-localization to actin stress fibers. DAAM1 siRNA knockdown significantly reduced co-precipitation of USP10 and DAAM1 on purified actin stress fibers, and β1- and β5-integrin ubiquitination. This resulted in increased αv-, β1-, and β5-integrin total protein levels, αv-integrin recycling, and extracellular fibronectin (FN) deposition. Together, our data demonstrate that DAAM1 inhibits USP10’s DUB activity on integrins subsequently regulating cell surface αv-integrin localization and FN accumulation.