title: The heterotrimeric motor protein kinesin-II localizes to the midpiece and flagellum of sea urchin and sand dollar sperm.
abstract: We have utilized immunoblotting and light microscopic immunofluorescent staining methods to examine the expression and localization of sea urchin kinesin-II, a heterotrimeric plus end-directed microtubule motor protein (previously referred to as KRP(85/95)), in sea urchin and sand dollar sperm. We demonstrate the presence of the 85 K and 115 K subunits of kinesin-II in sperm and localize these proteins to the sperm flagella and midpiece. The kinesin-II localization pattern is punctate and discontinuous, and in the flagella it is quite distinct from the continuous labeling present in sperm labeled with anti-flagellar dynein. The kinesin-II staining is largely insensitive to prefixation detergent extraction, suggesting that it is not associated with membranous elements in the sperm. In the midpiece the kinesin-II staining is similar to the pattern present in sperm labeled with an anti-centrosomal antibody. To our knowledge, this is the first localization of kinesin-like proteins in mature sperm and corroborates the recent identification and localization of kinesin-like proteins in the flagella and basal body of the unicellular green alga Chlamydomonas. We hypothesize that kinesin-II in the sperm may play functional roles in intraflagellar transport and/or the formation of flagella during spermatogenesis.
authors.affiliation: Department of Biology, Dickinson College, Carlisle, Pennsylvania 17013, USA. henson@dickinson.edu
authors.forename: J H
authors.initials: JH
authors.lastname: Henson
authors.forename: D G
authors.initials: DG
authors.lastname: Cole
authors.forename: C D
authors.initials: CD
authors.lastname: Roesener
authors.forename: S
authors.initials: S
authors.lastname: Capuano
authors.forename: R J
authors.initials: RJ
authors.lastname: Mendola
authors.forename: J M
authors.initials: JM
authors.lastname: Scholey
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000032:analysis*; D019084:Fluorescent Antibody Technique, Indirect; D016547:Kinesins; D008297:Male; D009124:Muscle Proteins / Q000032:analysis*; D012617:Sea Urchins / Q000737:chemistry* / Q000166:cytology; D013082:Sperm Tail / Q000737:chemistry*; D013094:Spermatozoa / Q000737:chemistry*
chemical_list: D002135:Calcium-Binding Proteins; D009124:Muscle Proteins; C074152:kinesin-II; D016547:Kinesins