A long version of Short stop

The Drosophila Short stop (Shot/Kakapo) gene encodes several protein isoforms, some of which may link integrins to microtubules. In analyzing the Shot locus, Röper and Brown (page 1305) found something odd: a previously unnoticed exon encoding a series of plakin repeats. The only known function of plakin repeats though is to interact with cytoplasmic intermediate filaments, which flies lack.

Based on a biochemical analysis, the plakin repeats are incorporated into a gigantic isoform of Shot that is the third-largest protein discovered in flies. This isoform includes an actin-binding domain, the plakin repeats, a microtubule-binding domain, and spectrin repeats, and is found in adherens junctions, a localization that seems to be determined by a portion of the plakin domain. Reducing the quantity of the largest Shot isoform in early embryos weakens epithelial intercellular contacts, so...