title: Selective diffusion barriers separate membrane compartments.
abstract: We have investigated exchange of molecules between different membrane domains on a highly compartmentalized cell, the spermatozoon. Using Alexa Fluor 555-cholera toxin B-subunit we have observed clustering of preexisting GM1 gangliosides which diffused across the anterior acrosome-equatorial segment interface but did not access the postacrosome. By contrast, single lipid and protein molecules readily exchanged between all three domains, although they diffused more slowly on nearing and crossing to the postacrosome. Thus, two types of diffusion interfaces are present on sperm heads, an "open" interface and a "mass filter" interface. The latter seems to be due to a protein-cytoskeleton network.
authors.affiliation: Department of Chemistry, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Andreas
authors.initials: A
authors.lastname: Bruckbauer
authors.forename: Paul D
authors.initials: PD
authors.lastname: Dunne
authors.forename: Peter
authors.initials: P
authors.lastname: James
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Howes
authors.forename: Dejian
authors.initials: D
authors.lastname: Zhou
authors.forename: Roy
authors.initials: R
authors.lastname: Jones
authors.forename: David
authors.initials: D
authors.lastname: Klenerman
mesh_terms: D000818:Animals; D002772:Cholera Toxin / Q000378:metabolism; D004058:Diffusion; D007700:Kinetics; D008297:Male; D021962:Membrane Microdomains / Q000378:metabolism*; D013094:Spermatozoa / Q000166:cytology* / Q000378:metabolism; D013552:Swine
chemical_list: D002772:Cholera Toxin