Radiya G. Ali
University of Queensland
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Publication
Featured researches published by Radiya G. Ali.
Current Biology | 2002
Eva M. Kovacs; Marita Goodwin; Radiya G. Ali; Andrew D. Paterson; Alpha S. Yap
Cadherin cell adhesion molecules are major determinants of tissue patterning which function in cooperation with the actin cytoskeleton. In the context of stable adhesion, cadherin/catenin complexes are often envisaged to passively scaffold onto cortical actin filaments. However, cadherins also form dynamic adhesive contacts during wound healing and morphogenesis. Here actin polymerization has been proposed to drive cell surfaces together, although F-actin reorganization also occurs as cell contacts mature. The interaction between cadherins and actin is therefore likely to depend on the functional state of adhesion. We sought to analyze the relationship between cadherin homophilic binding and cytoskeletal activity during early cadherin adhesive contacts. Dissecting the specific effect of cadherin ligation alone on actin regulation is difficult in native cell-cell contacts, due to the range of juxtacrine signals that can arise when two cell surfaces adhere. We therefore activated homophilic ligation using a specific functional recombinant protein. We report the first evidence that E-cadherin associates with the Arp2/3 complex actin nucleator and demonstrate that cadherin binding can exert an active, instructive influence on cells to mark sites for actin assembly at the cell surface.
Journal of Cell Biology | 2004
Falak M. Helwani; Eva M. Kovacs; Andrew D. Paterson; Suzie Verma; Radiya G. Ali; Alan S. Fanning; Scott A. Weed; Alpha S. Yap
Classical cadherin adhesion molecules are key determinants of cell–cell recognition during development and in post-embryonic life. A decisive step in productive cadherin-based recognition is the conversion of nascent adhesions into stable zones of contact. It is increasingly clear that such contact zone extension entails active cooperation between cadherin adhesion and the force-generating capacity of the actin cytoskeleton. Cortactin has recently emerged as an important regulator of actin dynamics in several forms of cell motility. We now report that cortactin is recruited to cell–cell adhesive contacts in response to homophilic cadherin ligation. Notably, cortactin accumulates preferentially, with Arp2/3, at cell margins where adhesive contacts are being extended. Recruitment of cortactin is accompanied by a ligation-dependent biochemical interaction between cortactin and the cadherin adhesive complex. Inhibition of cortactin activity in cells blocked Arp2/3-dependent actin assembly at cadherin adhesive contacts, significantly reduced cadherin adhesive contact zone extension, and perturbed both cell morphology and junctional accumulation of cadherins in polarized epithelia. Together, our findings identify a necessary role for cortactin in the cadherin–actin cooperation that supports productive contact formation.
Nature Cell Biology | 2011
Eva M. Kovacs; Suzie Verma; Radiya G. Ali; Aparna Ratheesh; Nicholas A. Hamilton; Anna Akhmanova; Alpha S. Yap
N-WASP is a major cytoskeletal regulator that stimulates Arp2/3-mediated actin nucleation. Here, we identify a nucleation-independent pathway by which N-WASP regulates the cytoskeleton and junctional integrity at the epithelial zonula adherens. N-WASP is a junctional protein whose depletion decreased junctional F-actin content and organization. However, N-WASP (also known as WASL) RNAi did not affect junctional actin nucleation, dominantly mediated by Arp2/3. Furthermore, the junctional effect of N-WASP RNAi was rescued by an N-WASP mutant that cannot directly activate Arp2/3. Instead, N-WASP stabilized newly formed actin filaments and facilitated their incorporation into apical rings at the zonula adherens. A major physiological effect of N-WASP at the zonula adherens thus occurs through a non-canonical pathway that is distinct from its capacity to activate Arp2/3. Indeed, the junctional impact of N-WASP was mediated by the WIP-family protein, WIRE, which binds to the N-WASP WH1 domain. We conclude that N-WASP–WIRE serves as an integrator that couples actin nucleation with the subsequent steps of filament stabilization and organization necessary for zonula adherens integrity.
Molecular Biology of the Cell | 2012
Suzie Verma; Siew Ping Han; Magdalene Michael; Guillermo A. Gomez; Zhe Yang; Rohan D. Teasdale; Aparna Ratheesh; Eva M. Kovacs; Radiya G. Ali; Alpha S. Yap
WAVE2–Arp2/3 is a major nucleator of actin assembly at the zonula adherens and likely acts in response to junctional Rac signaling. It supports myosin II recruitment to, and tension generation at, the junction.
Journal of Biological Chemistry | 2002
Eva M. Kovacs; Radiya G. Ali; Ailsa J. McCormack; Alpha S. Yap
American Journal of Physiology-cell Physiology | 2007
Astrid Kraemer; Marita Goodwin; Suzie Verma; Alpha S. Yap; Radiya G. Ali
The Medical Journal of Australia | 1977
Peter Brooks; J. Jones; R. Lawrence; Radiya G. Ali
Molecular Biology of the Cell | 2001
Alpha S. Yap; Radiya G. Ali; Marita Goodwin; Andrew D. Paterson; Jeanie A. Scott; Eva M. Kovacs
Archive | 2005
Radiya G. Ali
Molecular Biology of the Cell | 2001
Radiya G. Ali; Eva M. Kovacs; Alpha S. Yap