RESEARCH

Kinesins are a superfamily of molecular motor proteins that interact with microtubules to carry out cellular processes. All kinesin proteins contain a kinesin motor domain that binds both ATP and microtubules. Sequence differences within the kinesin motor domain endow kinesins with different mechanochemical and microtubule-based properties. Some kinesins are highly processive and capable of long-distance transport (e.g. members of the kinesin-1, kinesin-2 and kinesin-3 families) whereas others are immotile and may serve as tethers for signaling complexes (e.g. members of the kinesin-4, kinesin-9, and kinesin-11 families).

All microtubules are polymerized from the same building block, the protein tubulin, yet cells can generate functionally diverse microtubules that play specific roles in spatial organization, directional transport, and force generation. Microtubule diversity can arise from sequence differences across the tubulin isotypes encoded by the human genome and from post-translational modifications to tubulin subunits within a microtubule. This diversity has been proposed to generate a “Tubulin Code” that is recognized by cellular factors, i.e., “readers” that carry out specific microtubule-based functions.