We show for the first time, to our knowledge, that binding of vascular endothelial growth factor (VEGF) to the neuropilin-1 b1 domain is essential for VEGF complex formation with VEGFR2/KDR (kinase insert domain-containing receptor) and is important for endothelial cell migration and tubulogenesis

Neuropilin-1 (NRP1) is a receptor for vascular endothelial growth factor (VEGF) and plays an important role in mediating cell motility. However, the NRP1 signaling pathways important for cell motility are poorly understood. Here we report that p130Cas tyrosine phosphorylation is stimulated by hepatocyte growth factor and platelet-derived growth factor in U87MG glioma cells and VEGF in endothelial cells and is dependent on NRP1 via its intracellular domain. In endothelial cells, NRP1 silencing reduced, but did not prevent, VEGF receptor 2 (VEGFR2) phosphorylation, while expression of a mutant form of NRP1 lacking the intracellular domain (NRP1⌬C) did not affect receptor phosphorylation in U87MG cells or human umbilical vein endothelial cells (HUVECs). In HUVECs, NRP1 was also required for VEGF-induced phosphorylation of proline-rich tyrosine kinase 2, which was necessary for p130Cas phosphorylation. Importantly, knockdown of NRP1 or p130Cas or expression of either NRP1⌬C or a nontyrosine-phosphorylatable substrate domain mutant protein (p130 Cas15F ) was sufficient to inhibit growth factor-mediated migration of glioma and endothelial cells. These data demonstrate for the first time the importance of the NRP1 intracellular domain in mediating a specific signaling pathway downstream of several receptor tyrosine kinases and identify a critical role for a novel NRP1-p130Cas pathway in the regulation of chemotaxis.Neuropilin-1 (NRP1) is a coreceptor for vascular endothelial growth factor (VEGF) in endothelial cells and is essential for embryonic angiogenesis and vascular development (10,29). Though the precise cellular functions of NRP1 have yet to be elucidated, there is a growing body of evidence supporting a key role for NRP1 in the migration of both endothelial and tumor cells (9,11,15,19). NRP1 is thought to act as a coreceptor for VEGF by forming complexes with the VEGF receptor tyrosine kinase (RTK) VEGFR2. Complexation between NRP1 and VEGFR2 enhances VEGF binding, and inhibition of complex formation is associated with reduced VEGFR2 phosphorylation, intracellular signaling, mitogenesis, cell migration, and angiogenesis (16,18,28,34,35). However, the precise role of NRP1 in VEGF signaling remains unclear. Recent evidence indicates that NRP1 also regulates tumor and vascular cell functions stimulated by other growth factors, such as hepatocyte growth factor (HGF) and plateletderived growth factor (PDGF). Overexpression of NRP1 promotes tumor progression by potentiating the effect of the HGF/c-Met pathway, and tumor cell invasion mediated by the HGF/c-Met pathway is dependent on NRP1 through an association with c-Met (11, 15). Furthermore, NRP1 and NRP2 can bind HGF and mediate HGF stimulation of endothelial cell migration and proliferation (30). A recent report showed that NRP1 is also required for tumor cell-derived PDGF-mediated migration of smooth muscle cells (2). While these results indicate that NRP1 is required for optimal growth factor signaling important for cell motility, it remains unclear whether NR...

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A series of three experiments was designed to test predictions from a motivational systems approach to understanding the role of clinical constructs in anxiety-based problems. Negative mood, inflated responsibility, and intolerance of uncertainty (IU) were separately manipulated within analog samples to examine their effect on the other two factors. In the first experiment (n = 59) the negative mood group scored significantly higher in terms of inflated responsibility than the positive mood group. In the second experiment (n = 63) the high responsibility group scored significantly higher in terms of both negative mood and IU than the low responsibility group. In the third experiment (n = 61) the high IU group scored significantly higher in terms of negative mood than the low IU group. Tests of indirect effects revealed an indirect effect of IU on inflated responsibility through negative mood and an indirect effect of negative mood on IU through inflated responsibility, suggesting all three constructs are causally interrelated. The findings are consistent with contemporary transdiagnostic views of clinical constructs, and support a view of anxiety that is underpinned by a coordinated and interdependent motivational system evolved to manage threat.