Neuropilin-1 promotes VEGFR-2 trafficking through Rab11 vesicles thereby specifying signal output

K Ballmer-Hofer, AE Andersson… - Blood, The Journal …, 2011 - ashpublications.org
K Ballmer-Hofer, AE Andersson, LE Ratcliffe, P Berger
Blood, The Journal of the American Society of Hematology, 2011ashpublications.org
Vascular endothelial growth factors (VEGFs) regulate blood and lymph vessel development
by activating 3 receptor tyrosine kinases (RTKs), VEGFR-1,-2, and-3, and by binding to
coreceptors such as neuropilin-1 (NRP-1). We investigated how different VEGF-A isoforms,
in particular VEGF-A165a and VEGF-A165b, control the balance between VEGFR-2
recycling, degradation, and signaling. Stimulation of cells with the NRP-1–binding VEGF-
A165a led to sequential NRP-1–mediated VEGFR-2 recycling through Rab5, Rab4, and …
Abstract
Vascular endothelial growth factors (VEGFs) regulate blood and lymph vessel development by activating 3 receptor tyrosine kinases (RTKs), VEGFR-1, -2, and -3, and by binding to coreceptors such as neuropilin-1 (NRP-1). We investigated how different VEGF-A isoforms, in particular VEGF-A165a and VEGF-A165b, control the balance between VEGFR-2 recycling, degradation, and signaling. Stimulation of cells with the NRP-1–binding VEGF-A165a led to sequential NRP-1–mediated VEGFR-2 recycling through Rab5, Rab4, and Rab11 vesicles. Recycling was accompanied by dephosphorylation of VEGFR-2 between Rab4 and Rab11 vesicles and quantitatively and qualitatively altered signal output. In cells stimulated with VEGF-A165b, an isoform unable to bind NRP-1, VEGFR-2 bypassed Rab11 vesicles and was routed to the degradative pathway specified by Rab7 vesicles. Deletion of the GIPC (synectin) binding motif of NRP-1 prevented transition of VEGFR-2 through Rab11 vesicles and attenuated signaling. Coreceptor engagement was specific for VEGFR-2 because EGFR recycled through Rab11 vesicles in the absence of known coreceptors. Our data establish a distinct role of NRP-1 in VEGFR-2 signaling and reveal a general mechanism for the function of coreceptors in modulating RTK signal output.
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