Characterisation of the Rho GTPase target Dishevelled Associated Activator of Morphogenesis 1 (DAAM1)

Dishevelled Associated Activator of Morphogenesis 1 (DAAM1) is a formin which is important for gastrulation. In this thesis, we have sought to characterise DAAM1 in terms of its regulation and function. DAAM1 was found to localise to the perinuclear/Golgi region as well as to the actin/myosin II stress fibres. Truncation studies revealed that DAAM1 localisations to these regions were dependent on certain domains. DAAM1 binds to constitutively active RhoA, Rac1 and Cdc42 but binding did not affect its localisation. The putatively active construct, DAAM1 FH1-FH2-DAD, generated patches in HeLa cells which appeared dark under phase-contrast microscopy. These phase-dark patches co-stained with markers of lipid rafts and stable microtubules. When DAAM1 was knocked down in COS-7 cells in wound healing assays, Golgi/MTOC re-orientation towards the wound edge was impaired. We propose that DAAM1 could be an important player in cell polarisation via its effects on the actin and microtubule cytoskeleton.

Author dc:creator

• ANG SU FEN

• DAAM1, actin dynamics, centrosome orientation, cell migration, formins, Rho GTPase