The heterotrimeric motor protein kinesin-II localizes to the midpiece and flagellum of sea urchin and sand dollar sperm
✍ Scribed by Henson, John H. ;Cole, Douglas G. ;Roesener, Colleen D. ;Capuano, Stephanie ;Mendola, Robert J. ;Scholey, Jonathan M.
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 270 KB
- Volume
- 38
- Category
- Article
- ISSN
- 0886-1544
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✦ Synopsis
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.