Vimentin filaments in fibroblasts are a reservoir for SNAP23, a component of the membrane fusion machinery.
Soluble N-ethyl maleimide-sensitive fusion protein attachment protein receptors (SNAREs) are core machinery for membrane fusion during intracellular vesicular transport. Synaptosome-associated protein of 23 kDa (SNAP23) is a target SNARE previously identified at the plasma membrane, where it is involved in exocytotic membrane fusion. Here we show that SNAP23 associates with vimentin filaments in a Triton X-100 insoluble fraction in fibroblasts in primary culture and HeLa cells. Upon treatment of human fibroblasts with N-ethyl-maleimide, SNAP23 dissociates from vimentin filaments and forms a protein complex with syntaxin 4, a plasma membrane SNARE. The vimentin-associated pool of SNAP23 can therefore be a reservoir, which would supply the plasma membrane fusion machinery, in fibroblasts. Our observation points to a yet unexplored role of intermediate filaments.
Faigle
W
W
Group of Cellular Biology of Tumoral Immunity, Institut National de la Santé et de la Recherche Médicale U520, Institut Curie, F-75248 Paris Cédex 05, France.
Colucci-Guyon
E
E
Louvard
D
D
Amigorena
S
S
Galli
T
T
D000818:Animals; D002352:Carrier Proteins / Q000032:analysis / Q000502:physiology*; D005033:Ethylmaleimide / Q000494:pharmacology; D005347:Fibroblasts / Q000502:physiology* / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D007382:Intermediate Filaments / Q000187:drug effects / Q000648:ultrastructure*; D008561:Membrane Fusion / Q000187:drug effects / Q000502:physiology*; D008565:Membrane Proteins / Q000032:analysis; D051379:Mice; D018613:Microscopy, Confocal; D011092:Polyethylene Glycols; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D014404:Tubulin / Q000032:analysis; D014746:Vimentin / Q000032:analysis / Q000502:physiology*
D002352:Carrier Proteins; D008565:Membrane Proteins; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; C100493:SNAP23 protein, human; C107017:Snap23 protein, mouse; D014404:Tubulin; D014746:Vimentin; D011092:Polyethylene Glycols; D005033:Ethylmaleimide