Quantitative proteomics identifies a Dab2/integrin module regulating cell migration. J Cell Biol

Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
The Journal of Cell Biology (Impact Factor: 9.69). 08/2009; 186(1):99-111. DOI: 10.1083/jcb.200812160
Source: PubMed

ABSTRACT Clathrin-associated endocytic adapters recruit cargoes to coated pits as a first step in endocytosis. We developed an unbiased quantitative proteomics approach to identify and quantify glycoprotein cargoes for an endocytic adapter, Dab2. Surface levels of integrins beta1, alpha1, alpha2, and alpha3 but not alpha5 or alphav chains were specifically increased on Dab2-deficient HeLa cells. Dab2 colocalizes with integrin beta1 in coated pits that are dispersed over the cell surface, suggesting that it regulates bulk endocytosis of inactive integrins. Depletion of Dab2 inhibits cell migration and polarized movement of integrin beta1 and vinculin to the leading edge. By manipulating intracellular and surface integrin beta1 levels, we show that migration speed correlates with the intracellular integrin pool but not the surface level. Together, these results suggest that Dab2 internalizes integrins freely diffusing on the cell surface and that Dab2 regulates migration, perhaps by maintaining an internal pool of integrins that can be recycled to create new adhesions at the leading edge.

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    • "We do not expect cell attachment on surface is affected by cycloheximide treatment, since attachment, unlike adhesion, is too fast to rely on protein synthesis (it takes place in some minutes). Moreover, for attachment , cells use receptors that are already exposed on cell surface or are supplied by exocytosis of integrin-recycled containing vesicles [38] [39] [40]. "
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    ABSTRACT: The development of materials that allow proper functioning of cells on solid supports is directly relevant to the construction of living-cell biosensors. Both physical and chemical properties of the surfaces have been shown to be critical in this field. Our aim is to report correlations between chemical properties of surfaces and cell behavior by studying adhesion, viability and proliferation of fibroblasts and HeLa cells. Neither fibroblasts nor HeLa cells adhered to a hydrophobic surface. Fibroblasts were able to attach and proliferate well on all other surfaces tested. In contrast, on some surfaces where HeLa cells adhered and were viable, proliferation decreased by half while on others proliferation was not affected. Proliferation was significantly correlated with the level of adsorption of serum proteins on the surface (quantified by surface plasmon resonance), but not with surface wettability (water contact angle). Interestingly, surfaces modified with COOH and HSO3 groups were the ones that favored most protein adsorption and allowed the best measures for HeLa cell proliferation. The decrease of HeLa cell proliferation on surfaces covered with poly-l-lysine (PL) was related with the profile of integrin expression. Compared to a polystyrene control surface, there was an increase in αV and αVβ3 and a decrease in α2 and α3, indicating that migration rather than proliferation could be favored on PL functionalized surfaces. These results indicate that charge is more important than wettability to determine biocompatibility. Copyright © 2014. Published by Elsevier B.V.
    Colloids and surfaces B: Biointerfaces 10/2014; 123. DOI:10.1016/j.colsurfb.2014.09.034 · 4.15 Impact Factor
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    • "It has been shown that Numb regulates Integrin-b turnover in vitro (Nishimura and Kaibuchi, 2007; Teckchandani et al., 2009). To determine whether Numb also functions as a regulator of focal adhesions in the retinal epithelium, we generated retinal clones overexpressing numb and monitored Integrin-b1 localization (Figures 5G–5P). "
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    Developmental Cell 10/2012; 23(4):782-95. DOI:10.1016/j.devcel.2012.09.004 · 10.37 Impact Factor
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    • "integrins binding talin but not ECM ligands) along the leading edge to newly formed protrusions (Galbraith et al., 2007), suggesting that the final targeting of the active integrin receptor to adhesion sites is driven by actin. In cells, inactive integrins are often found located in detached ruffles (Rantala et al., 2011) or dorsally (Teckchandani et al., 2009 "
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    ABSTRACT: Integrins are heterodimeric transmembrane adhesion receptors composed of α- and β-subunits. They are ubiquitously expressed and have key roles in a number of important biological processes, such as development, maintenance of tissue homeostasis and immunological responses. The activity of integrins, which indicates their affinity towards their ligands, is tightly regulated such that signals inside the cell cruicially regulate the switching between active and inactive states. An impaired ability to activate integrins is associated with many human diseases, including bleeding disorders and immune deficiencies, whereas inappropriate integrin activation has been linked to inflammatory disorders and cancer. In recent years, the molecular details of integrin 'inside-out' activation have been actively investigated. Binding of cytoplasmic proteins, such as talins and kindlins, to the cytoplasmic tail of β-integrins is widely accepted as being the crucial step in integrin activation. By contrast, much less is known with regard to the counteracting mechanism involved in switching integrins into an inactive conformation. In this Commentary, we aim to discuss the known mechanisms of integrin inactivation and the molecules involved.
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