Co-localization of receptor and transducer proteins in the glycosphingolipid-enriched, low density, detergent-insoluble membrane fraction of sea urchin sperm.
The low density, detergent-insoluble membrane fraction (LD-DIM), where gangliosides are likely to be highly enriched, was prepared from sperm of two sea urchin species, Hemicentrotus pulcherrimus and Strongylocentrotus purpuratus. Immunoblotting showed the presence in the LD-DIM of two receptors for egg ligands, a glycosylphosphatidylinositol (GPI)-anchored protein, and four proteins which may be involved in signal transduction. Co-immunoprecipitation revealed that at least three proteins, the speract receptor, the 63kDa GPI-anchored protein and the alpha subunit of a heterotrimeric Gs protein, are localized in the LD-DIM. This suggests that the LD-DIM fraction may be a membrane microdomain for speract-speract receptor interaction, as well as the subsequent signal transduction pathway involved in induction of sperm respiration, motility and possibly the acrosome reaction.
Ohta
K
K
Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Japan.
Sato
C
C
Matsuda
T
T
Toriyama
M
M
Vacquier
V D
VD
Lennarz
W J
WJ
Kitajima
K
K
D000818:Animals; D015153:Blotting, Western; D002240:Carbohydrate Sequence; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D003902:Detergents / Q000737:chemistry*; D005455:Fluorescent Antibody Technique; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000378:metabolism*; D005732:Gangliosides / Q000276:immunology / Q000378:metabolism; D006028:Glycosphingolipids / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D011233:Precipitin Tests; D011956:Receptors, Cell Surface / Q000378:metabolism*; D012617:Sea Urchins; D012995:Solubility; D013094:Spermatozoa / Q000737:chemistry* / Q000378:metabolism
D003902:Detergents; D005732:Gangliosides; D006028:Glycosphingolipids; D011956:Receptors, Cell Surface; C035027:egg surface sperm receptor; D019205:GTP-Binding Protein alpha Subunits, Gs