Here, we report a direct interaction between the beta1 integrin cytoplasmic tail and Rab25, a GTPase that has been linked to tumor aggressiveness and metastasis. Rab25 promotes a mode of migration on ...3D matrices that is characterized by the extension of long pseudopodia, and the association of the GTPase with alpha5beta1 promotes localization of vesicles that deliver integrin to the plasma membrane at pseudopodial tips as well as the retention of a pool of cycling alpha5beta1 at the cell front. Furthermore, Rab25-driven tumor-cell invasion into a 3D extracellular matrix environment is strongly dependent on ligation of fibronectin by alpha5beta1 integrin and the capacity of Rab25 to interact with beta1 integrin. These data indicate that Rab25 contributes to tumor progression by directing the localization of integrin-recycling vesicles and thereby enhancing the ability of tumor cells to invade the extracellular matrix.
Here, we report a direct interaction between the ^b1 integrin cytoplasmic tail and Rab25, a GTPase that has been linked to tumor aggressiveness and metastasis. Rab25 promotes a mode of migration on ...3D matrices that is characterized by the extension of long pseudopodia, and the association of the GTPase with 5^b1 promotes localization of vesicles that deliver integrin to the plasma membrane at pseudopodial tips as well as the retention of a pool of cycling 5^b1 at the cell front. Furthermore, Rab25-driven tumor-cell invasion into a 3D extracellular matrix environment is strongly dependent on ligation of fibronectin by 5^b1 integrin and the capacity of Rab25 to interact with ^b1 integrin. These data indicate that Rab25 contributes to tumor progression by directing the localization of integrin-recycling vesicles and thereby enhancing the ability of tumor cells to invade the extracellular matrix.
The dynamic control of E-cadherin is critical for establishing and maintaining cell-cell junctions in epithelial cells. The concentration of E-cadherin molecules at adherens junctions (AJs) is ...regulated by lateral movement of E-cadherin within the plasma membrane and endocytosis. Here we set out to study the interplay between these processes and their contribution to E-cadherin dynamics. Using photoactivation (PA) and fluorescence recovery after photobleaching (FRAP) we were able to monitor the fate of E-cadherin molecules within the plasma membrane. Our results suggest that the motility of E-cadherin within, and away from, the cell surface are not exclusive or independent mechanisms and there is a fine balance between the two which when perturbed can have dramatic effects on the regulation of AJs.
Modern biological research depends on a wide variety of specialized techniques, which collectively are beyond the grasp of a single research group. Research infrastructure, in the form of services ...and facilities, is therefore an increasingly important foundation for a competitive research institution. A lightmicroscopy facility is a place of dynamic interaction among users, staff, and equipment. Staff provide the organization, continuity, and expert knowledge required to manage the laser-safe interaction between demanding, selfish, high-performance users and delicate, expensive, high-performance equipment. They introduce novice users to fundamental principles of image acquisition and analysis, often beginning with fluorescence basics, but collaborate with advanced users in the development of new imaging techniques. Intimate knowledge of the experimental needs of the user research groups is required to maximize the effectiveness of equipment purchases, which are also informed by critical evaluation of local sales and support teams. Equipment management encompasses evaluation, purchase, installation, operation, and maintenance, and depends critically on good relations with competent local technical support. Special care should be given to the architectural design of an imaging facility to maximize the utility and comfort of the user environment and the long-term performance stability of the equipment. Finally, we present the details of a web-based equipment scheduling database as an essential organizational tool for running an imaging facility, and outline the important points underlying the estimation of hourly instrument costs in a fee-for-use setting.
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