DICTYOSTELIUM MYOSIN-II NULL MUTANT CAN STILL CAP CON-A RECEPTORS

Cross-linked antigens on the surface of a motile cell cap at the trail ing end of the cell. In Dictyostelium discoideum, myosin II null mutan ts have previously been reported to be unable to cap Con A receptors, although they are able to locomote. This finding implicated myosin II as an essential component of the capping mechanism, although not of th e machinery for locomotion. Here we show that myosin II null mutants d o cap Con A receptors, albeit less efficiently than does wild type. Th is shows that cap formation is not absolutely dependent on myosin II a nd that a close mechanistic relationship between capping, particle mov ement, and cell migration may still exist.