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Title: Bovine binder-of-sperm protein BSP1 promotes protrusion and nanotube formation from liposomes

Journal Article · · Biochemical and Biophysical Research Communications
 [1];  [1]; ;  [2];  [3];  [4]
  1. Department of Chemistry, Center for Self-Assembled Chemical Systems, Universite de Montreal, C.P. 6128, Succ. Centre Ville, Montreal, Quebec, Canada H3C 3J7 (Canada)
  2. Department of Physical and Analytical Chemistry, Uppsala University, Box 579, S-751 23 Uppsala (Sweden)
  3. Department of Physiology, Groupe d'etude des Proteines Membranaires, Universite de Montreal, C.P. 6128, Succ. Centre Ville, Montreal, Quebec, Canada H3C 3J7 (Canada)
  4. Maisonneuve-Rosemont Hospital Research Center and Faculty of Medecine, Universite de Montreal, 5415 L'Assomption Blvd, Montreal, Quebec, Canada H1T 2M4 (Canada)

Research highlights: {yields} Binder-of-sperm protein 1 (BSP1) modifies the morphology of lipidic vesicles inducing bead necklace-like and thread-like structures. {yields} In the presence of multilamellar liposomes, BSP1 leads to the formation of long nanotubes. {yields} The insertion of BSP1 in the external lipid leaflet of membranes induces local changes in bilayer curvature. -- Abstract: Binder-of-sperm (BSP) proteins interact with sperm membranes and are proposed to extract selectively phosphatidylcholine and cholesterol from these. This change in lipid composition is a key step in sperm capacitation. The present work demonstrates that the interactions between the protein BSP1 and model membranes composed with phosphatidylcholine lead to drastic changes in the morphology of the lipidic self-assemblies. Using cryo-electron microscopy and fluorescence microscopy, we show that, in the presence of the protein, the lipid vesicles elongate, and form bead necklace-like structures that evolve toward small vesicles or thread-like structures. In the presence of multilamellar vesicles, where a large reservoir of lipid is available, the presence of BSP proteins lead to the formation of long nanotubes. Long spiral-like threads, associated with lipid/protein complexes, are also observed. The local curvature of lipid membranes induced by the BSP proteins may be involved in lipid domain formation and the extraction of some lipids during the sperm maturation process.

OSTI ID:
22202752
Journal Information:
Biochemical and Biophysical Research Communications, Vol. 399, Issue 3; Other Information: Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0006-291X
Country of Publication:
United States
Language:
English