title: Recycling endosome membrane incorporation into the leading edge regulates lamellipodia formation and macrophage migration.
abstract: In comparison to our knowledge of the recycling of adhesion receptors and actin assembly, exactly how the cell controls its surface membrane to form a lamellipodium during migration is poorly understood. Here, we show the recycling endosome membrane is incorporated into the leading edge of a migrating cell to expand lamellipodia membrane. We have identified the SNARE complex that is necessary for fusion of the recycling endosome with the cell surface, as consisting of the R-SNARE VAMP3 on the recycling endosome partnering with the surface Q-SNARE Stx4/SNAP23, which was found to translocate and accumulate on the leading edge of migrating cells. Increasing VAMP3-mediated fusion of the recycling endosome with the surface increased membrane ruffling, while inhibition of VAMP3-mediated fusion showed that incorporation of the recycling endosome is necessary for efficient lamellipodia formation. At the same time, insertion of this recycling endosome membrane also delivers its cargo integrin α5β1 to the cell surface. The loss of this extra membrane for lamellipodia expansion and delivery of cargo in cells resulted in macrophages with a diminished capacity to effectively migrate. Thus, the recycling endosome membrane is incorporated into the leading edge and this aids expansion of the lamellipodia and simultaneously delivers integrins necessary for efficient cell migration.
authors.affiliation: CHBRI Wound Healing Laboratory, Kids Research Institute, The Children's Hospital at Westmead, Westmead, Sydney, NSW, Australia.
authors.forename: Kelly J
authors.initials: KJ
authors.lastname: Veale
authors.forename: Carolin
authors.initials: C
authors.lastname: Offenhäuser
authors.forename: Shane P
authors.initials: SP
authors.lastname: Whittaker
authors.forename: Ruby P
authors.initials: RP
authors.lastname: Estrella
authors.forename: Rachael Z
authors.initials: RZ
authors.lastname: Murray
mesh_terms: D000818:Animals; D002460:Cell Line; D002465:Cell Movement; D011992:Endosomes / Q000378:metabolism*; D039081:Integrin alpha5beta1 / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism*; D008561:Membrane Fusion; D051379:Mice; D011554:Pseudopodia / Q000378:metabolism*; D050766:Qb-SNARE Proteins / Q000378:metabolism; D050767:Qc-SNARE Proteins / Q000378:metabolism; D051040:Vesicle-Associated Membrane Protein 3 / Q000378:metabolism
chemical_list: D039081:Integrin alpha5beta1; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; C107017:Snap23 protein, mouse; D051040:Vesicle-Associated Membrane Protein 3; C494953:vesicle-associated membrane protein 3, mouse