Universal and Unique Features of Kinesin Motors: Insights from a Comparison of Fungal and Animal Conventional Kinesins

Abstract

Kinesins are microtubule motors that use the energy derived from the hydrolysis of ATP to move unidirectionally along microtubules. The founding member of this still growing superfamily is conventional kinesin, a dimeric motor that moves processively towards the plus end of microtubules. Within the family of conventional kinesins, two groups can be distinguished to date, one derived from animal species, and one originating from filamentous fungi. So far no conventional kinesin has been reported from plant cells. Fungal and animal conventional kinesins differ in several respects, both in terms of their primary sequence and their physiological properties. Thus all fungal conventional kinesins move at velocities that are 4 -5 times higher than those of animal conventional kinesins, and all of them appear to lack associated light chains. Both groups of motors are characterized by a number of group-specific sequence features which are considered here with respect to their functional importance. Animal and fungal conventional kinesins also share a number of sequence characteristics which point to common principles of motor function. The overall domain organization is remarkably similar. A C-terminal sequence motif common to all kinesins, which constitutes the only region of high homology outside the motor domain, suggests common principles of cargo association in both groups of motors. Consideration of the differences of, and similarities between, fungal and animal kinesins offers novel possibilities for experimentation (e. g., by constructing chimeras) that can be expected to contribute to our understanding of motor function.

Kinectin-Kinesin Binding Domains and Their Effects on Organelle Motility

“…This is the only highly conserved region on kinesin other than the motor domain on the kinesin head (51). Therefore, it is not surprising that all three members of the human conventional kinesin family interact with kinectin in our assays.…”

“…We have also constructed a series of deletion mutants of kinectin and kinesin and characterized the minimally sufficient sites for the kinectin-kinesin interaction. The kinectin-binding domain on kinesin resides near the COOH terminus within a region called the "coiled-coil tail," which is adjacent to the globular tail at the extreme COOH terminus (51). This coiled-coil tail has been postulated as the cargo-binding domain on kinesin (34).…”

Lessons from the Genome Sequence ofNeurospora crassa: Tracing the Path from Genomic Blueprint to Multicellular Organism

“…Mutational analysis of Nkin has identified regions of cargo association and regulation of the ATPase activity that are conserved between fungal and animal kinesins (421,700). Interestingly, fungal conventional kinesins lack copurifying light chains (422), which, in addition to the C terminus of the motor protein itself, were proposed to function in cargo attachment and motor activation in animals (830), suggesting that this fungal motor could serve as a simplified model to study motor-cargo interaction and its regulation.…”

Single molecule mechanics of the kinesin neck

“…1A) (11). Both structurally and thermodynamically, the Kinesin-1 neck can be divided into a highly conserved N-terminal segment I (brown and pink in Fig.…”