Identification of mouse trp homologs and lipid rafts from spermatogenic cells and sperm.
Intracellular Ca(2+) has an important regulatory role in the control of sperm motility, capacitation, and the acrosome reaction (AR). However, little is known about the molecular identity of the membrane systems that regulate Ca(2+) in sperm. In this report, we provide evidence for the expression of seven Drosophila transient receptor potential homolog genes (trp1-7) and three of their protein products (Trp1, Trp3 and Trp6) in mouse sperm. Allegedly some trps encode capacitative Ca(2+) channels. Immunoconfocal images showed that while Trp6 was present in the postacrosomal region and could be involved in sperm AR, expression of Trp1 and Trp3 was confined to the flagellum, suggesting that they may serve sperm to regulate important Ca(2+)-dependent events in addition to the AR. Likewise, one of these proteins (Trp1) co-immunolocalized with caveolin-1, a major component of caveolae, a subset of lipid rafts potentially important for signaling events and Ca(2+) flux. Furthermore, by using fluorescein-coupled cholera toxin B subunit, which specifically binds to the raft component ganglioside GM1, we identified caveolin- and Trp-independent lipid rafts residing in the plasma membrane of mature sperm. Notably, the distribution of GM1 changes drastically upon completion of the AR.
Treviño
C L
CL
Department of Genetics and Molecular Physiology, Institute of Biotechnology, UNAM, Cuernavaca, Mexico.
Serrano
C J
CJ
Beltrán
C
C
Felix
R
R
Darszon
A
A
D020101:Acrosome Reaction; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000096:biosynthesis* / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D002772:Cholera Toxin / Q000378:metabolism; D029721:Drosophila Proteins; D019476:Insect Proteins / Q000096:biosynthesis* / Q000235:genetics*; D008297:Male; D021962:Membrane Microdomains / Q000378:metabolism*; D051379:Mice; D018613:Microscopy, Confocal; D012313:RNA / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013090:Spermatocytes / Q000378:metabolism*; D013091:Spermatogenesis; D013094:Spermatozoa / Q000378:metabolism*; D050052:TRPC Cation Channels; D014161:Transduction, Genetic; D050051:Transient Receptor Potential Channels
D015220:Calcium Channels; D029721:Drosophila Proteins; D019476:Insect Proteins; D050052:TRPC Cation Channels; D050051:Transient Receptor Potential Channels; C096351:transient receptor potential cation channel, subfamily C, member 1; C063169:trp protein, Drosophila; D012313:RNA; D002772:Cholera Toxin; D002118:Calcium