Functional and molecular diversity of dynein heavy chains

The directed translocation of dynein along microtubules is the basis for a wide variety of essential cellular movements. In eukaryotic flagella and cilia, dynein produces the active sliding of outer doublet microtubules that underlies axonemal bending Several dynein heavy chain isoforms are precisely located in the axoneme in order to initiate and propagate bends, and it is believed that these different isoforms produce distinct shear forces. Analysis of the sequences cf dynein isoforms suggests that the specialization in force production may be a consequence of the protein sequence of the dynein catalytic domain. Recent evidence for multiple isoforms of cytoplasmic dynein leads to the hypothesis that cytoplasmic dynein isoforms are individually tailored to produce specific forces or to carry separate cargoes.