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A proteomics approach to isolating neuropilin-dependent α5 integrin trafficking pathways: neuropilin 1 and 2 co-traffic α5 integrin through endosomal p120RasGAP to promote polarised fibronectin fibrillogenesis in endothelial cells.

Published version
Peer-reviewed

Repository DOI


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Authors

Benwell, Christopher J  ORCID logo  https://orcid.org/0000-0003-0579-7920
Taylor, James AGE 
Robinson, Stephen D  ORCID logo  https://orcid.org/0000-0002-6606-7588

Abstract

Integrin trafficking to and from membrane adhesions is a crucial mechanism that dictates many aspects of a cell's behaviour, including motility, polarisation, and invasion. In endothelial cells (ECs), the intracellular traffic of α5 integrin is regulated by both neuropilin 1 (NRP1) and neuropilin 2 (NRP2), yet the redundancies in function between these co-receptors remain unclear. Moreover, the endocytic complexes that participate in NRP-directed traffic remain poorly annotated. Here we identify an important role for the GTPase-activating protein p120RasGAP in ECs, promoting the recycling of α5 integrin from early endosomes. Mechanistically, p120RasGAP enables transit of endocytosed α5 integrin-NRP1-NRP2 complexes to Rab11+ recycling endosomes, promoting cell polarisation and fibronectin (FN) fibrillogenesis. Silencing of both NRP receptors, or p120RasGAP, resulted in the accumulation of α5 integrin in early endosomes, a loss of α5 integrin from surface adhesions, and attenuated EC polarisation. Endothelial-specific deletion of both NRP1 and NRP2 in the postnatal retina recapitulated our in vitro findings, severely impairing FN fibrillogenesis and polarised sprouting. Our data assign an essential role for p120RasGAP during integrin traffic in ECs and support a hypothesis that NRP receptors co-traffic internalised cargoes. Importantly, we utilise comparative proteomics analyses to isolate a comprehensive map of NRP1-dependent and NRP2-dependent α5 integrin interactions in ECs.

Description

Acknowledgements: This work was supported by funding from BHF (grant number PG/22/11033); S.D.R. gratefully acknowledges the support of the Biotechnology and Biological Sciences Research Council (BBSRC); this research was partially funded by the BBSRC Institute Strategic Programme Food Microbiome and Health BB/X011054/1 and its constituent project BBS/E/F/000PR13632.

Keywords

Animals, Mice, Endosomes, Endothelial Cells, Fibronectins, Integrin alpha5, Integrins, Neuropilin-1, Neuropilin-2, p120 GTPase Activating Protein, Protein Transport, Proteomics

Journal Title

Commun Biol

Conference Name

Journal ISSN

2399-3642
2399-3642

Volume Title

7

Publisher

Springer Science and Business Media LLC
Sponsorship
British Heart Foundation (BHF) (PG/22/11033, PG/22/11033)
RCUK | Biotechnology and Biological Sciences Research Council (BBSRC) (BB/X011054/1, BBS/E/F/000PR13632)