Cell Culture

On June 11 th , the best soccer players from around the world will meet in South Africa at the FIFA 2010 World Cup. To reach this level of competition, these players combine phenomenal ball-handling skills with three major characteristics: fast sprinting, rapid reaction times, and ferocious tenacity. This issue's Cell Culture explores these three athletic qualities from a molecular and cellular perspective, but first we delve into the design details of FIFA's newest soccer ball. At the 2010 World Cup, FIFA will unveil its ''next-generation'' soccer ball. Departing from the traditional architecture, the new ball contains only 8 panels instead of the classic 20 hexagonal and 12 pentagonal sections. Moreover, the panels are thermally bonded instead of stitched together, providing superior aerodynamics and less ''flutter'' in the air. Unlike FIFA, cells are not retiring the traditional hexagon-pentagon pattern anytime soon; this poly-hedral architecture is simply too handy for forming spherical shapes with flexible sizes and curvatures. From a design perspective, removing the stitches from the soccer ball is analogous to removing the coat proteins from cellular transport vesicles (Fotin et al.). Cells traffic material around the cytoplasm in membrane-bound pouches, called vesi-cles. Coat proteins shape and stabilize a vesicle by covering its outside surface. For example, the clathrin protein assembles into a lattice-like shell with pentagonal and hexagonal facets. Hexagons form at flat faces of vesicles, and pentagons are added to introduce curvature. This alternating pentagon-hexagon architecture is extremely adaptable. Whereas 8 hexagons with 12 pentagons form a barrel-shaped lattice, 12 hexagons with 12 pentagons assemble into a ''soccer ball'' with a diameter of 100 nm (Fotin et al.). The pentagon-hexagon pattern also appears at larger scales in biological systems. For example, the back of the jeweled beetle, Chrysina gloriosa, glows metallic green under polarized light. Sharma et al. found that the beetle derives its sheen from the interaction of light with hexagonal panels of chitin on its exoskeleton that are interspersed with pentagonal and heptagonal panels. The frequency of pentagons increases in regions of the beetle's back with the greatest curvature. Therefore, these smaller panels, which are 30,000 times larger than the pentagons of clathrin, serve a similar purpose here as in coated vesi-cles and soccer balls; they permit the efficient tiling of curved surfaces without any gaps or holes. A key difference between mediocre soccer players and the crè me-de-la-crè me is their reaction times. Elite players …