Dendritic spines are the major sites of excitatory synaptic input, and their morphological changes have been linked to learning and memory processes. Here, we report that growing microtubule plus ends decorated by the microtubule tip-tracking protein EB3 enter spines and can modulate spine morphology. We describe p140Cap/SNIP, a regulator of Src tyrosine kinase, as an EB3 interacting partner that is predominantly localized to spines and enriched in the postsynaptic density. Inhibition of microtubule dynamics, or knockdown of either EB3 or p140Cap, modulates spine shape via regulation of the actin cytoskeleton. Fluorescence recovery after photobleaching revealed that EB3-binding is required for p140Cap accumulation within spines. In addition, we found that p140Cap interacts with Src substrate and F-actin-binding protein cortactin. We propose that EB3-labeled growing microtubule ends regulate the localization of p140Cap, control cortactin function, and modulate actin dynamics within dendritic spines, thus linking dynamic microtubules to spine changes and synaptic plasticity.

R.Soldi and S.Mitola contributed equally to this workInteraction between integrin α v β 3 and extracellular matrix is crucial for endothelial cells sprouting from capillaries and for angiogenesis. Furthermore, integrinmediated outside-in signals co-operate with growth factor receptors to promote cell proliferation and motility. To determine a potential regulation of angiogenic inducer receptors by the integrin system, we investigated the interaction between α v β 3 integrin and tyrosine kinase vascular endothelial growth factor receptor-2 (VEGFR-2) in human endothelial cells. We report that tyrosine-phosphorylated VEGFR-2 co-immunoprecipitated with β3 integrin subunit, but not with β1 or

Adhesion of human primary skin fibroblasts and ECV304 endothelial cells to immobilized matrix proteins, β1 or αv integrin antibodies stimulates tyrosine phosphorylation of the epidermal growth factor (EGF) receptor. This tyrosine phosphorylation is transiently induced, reaching maximal levels 30 min after adhesion, and it occurs in the absence of receptor ligands. Similar results were observed with EGF receptor-transfected NIH-3T3 cells. Use of a kinasenegative EGF receptor mutant demonstrates that the integrin-stimulated tyrosine phosphorylation is due to activation of the receptor's intrinsic kinase activity. Integrin-mediated EGF receptor activation leads to Erk-1/MAP kinase induction, as shown by treatment with the specific inhibitor tyrphostin AG1478 and by expression of a dominant-negative EGF receptor mutant. EGF receptor and Erk-1/MAP kinase activation by integrins does not lead per se to cell proliferation, but is important for entry into S phase in response to EGF or serum. EGF receptor activation is also required for extracellular matrix-mediated cell survival. Adhesion-dependent MAP kinase activation and survival are regulated through EGF receptor activation in cells expressing this molecule above a threshold level (5⍥10 3 receptors per cell). These results demonstrate that integrin-dependent EGF receptor activation is a novel signaling mechanism involved in cell survival and proliferation in response to extracellular matrix.

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Integrin-mediated cell adhesion cooperates with growth factor receptors in the control of cell proliferation, cell survival, and cell migration. One mechanism to explain these synergistic effects is the ability of integrins to induce phosphorylation of growth factor receptors, for instance the epidermal growth factor (EGF) receptor. Here we define some aspects of the molecular mechanisms regulating integrin-dependent EGF receptor phosphorylation. We show that in the early phases of cell adhesion integrins associate with EGF receptors on the cell membrane in a macromolecular complex including the adaptor protein p130Cas and the c-Src kinase, the latter being required for adhesion-dependent assembly of the macromolecular complex. We also show that the integrin cytoplasmic tail, c-Src kinase, and the p130Cas adaptor protein are required for phosphorylation of EGF receptor in response to integrin-mediated adhesion. We show that integrins induce phosphorylation of EGF receptor on tyrosine residues 845, 1068, 1086, and 1173, but not on residue 1148, a major site of phosphorylation in response to EGF. In addition we find that integrin-mediated adhesion increases the amount of EGF receptor expressed on the cell surface. Therefore these data indicate that integrin-mediated adhesion induces assembly of a macromolecular complex containing c-Src and p130Cas and leads to phosphorylation of specific EGF receptor tyrosine residues.

Current evidence highlights the ability of adaptor (or scaffold) proteins to create signalling platforms that drive cellular transformation upon integrin-dependent adhesion and growth factor receptor activation. The understanding of the biological effects regulated by these adaptors in tumours might be crucial for the identification of novel targets and the development of innovative therapeutic strategies for human cancer. In this review we will discuss the relevance of adaptor proteins in signalling originating from integrin-mediated cell-extracellular matrix (ECM) adhesion and growth factor stimulation within the context of cell transformation and tumour progression.Herein, we will specifically underline the contribution of p130CAS, NEDD9, CRK, and the IPP complex (ILK, PINCH and PARVIN) to cancer, along with the more recently identified p140CAP.

Granulocyte-colony stimulating factor (G-CSF) and granulocyte-macrophage-colony stimulating factor (GM-CSF) belong to a family of glycoprotidic growth factors required for the survival, growth and differentiation of haematopoietic precursors and which affect the function of circulating mature cells. They are produced by resting or stimulated stromal cells of the haematopoietic microenvironment (fibroblasts and endothelium) and by immunocompetent cells (T cells and monocytes/macrophages). The action of these CSF molecules was thought to be restricted to cells of haematopoietic origin. Here, we report that G-CSF and GM-CSF influence the migration and proliferation of human endothelial cells suggesting that these molecules may act as regulatory signals outside the haematopoietic system.

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