Control of motor landing and processivity by the CAP-Gly domain in the KIF13B tail

Intracellular transport of material along microtubules by kinesin motors is critical for cellular homeostasis. Here the authors uncover a unique role for a specialized kinesin tail domain in directing motor transport along specific microtubule tracks. Microtubules are major components of the eukaryotic cytoskeleton. Posttranslational modifications (PTMs) of tubulin regulates interactions with microtubule-associated proteins (MAPs). One unique PTM is the cyclical removal and re-addition of the C-terminal tyrosine of & alpha;-tubulin and MAPs containing CAP-Gly domains specifically recognize tyrosinated microtubules. KIF13B, a long-distance transport kinesin, contains a conserved CAP-Gly domain, but the role of the CAP-Gly domain in KIF13B's motility along microtubules remains unknown. To address this, we investigate the interaction between KIF13B's CAP-Gly domain, and tyrosinated microtubules. We find that KIF13B's CAP-Gly domain influences the initial motor-microtubule interaction, as well as processive motility along microtubules. The effect of the CAP-Gly domain is enhanced when the motor domain is in the ADP state, suggesting an interplay between the N-terminal motor domain and C-terminal CAP-Gly domain. These results reveal that specialized kinesin tail domains play active roles in the initiation and continuation of motor movement.

Automated summary

This study reveals the crucial role of a specialized kinesin tail domain in directing motor transport along specific microtubule tracks. The tail domain affects the initial motor-microtubule interaction and the processive motility, and its effect is enhanced when the motor domain is in the ADP state.