Identification of key residues that regulate the interaction of kinesins with microtubule ends

Hannah R Belsham,Claire T Friel

doi:10.1002/cm.21568

Abstract

Kinesins are molecular motors that use energy derived from ATP turnover to walk along microtubules, or when at the microtubule end, regulate growth or shrinkage. All kinesins that regulate microtubule dynamics have long residence times at microtubule ends, whereas those that only walk have short end‐residence times. Here, we identify key amino acids involved in end binding by showing that when critical residues from Kinesin‐13, which depolymerises microtubules, are introduced into Kinesin‐1, a walking kinesin with no effect on microtubule dynamics, the end‐residence time is increased up to several‐fold. This indicates that the interface between the kinesin motor domain and the microtubule is malleable and can be tuned to favour either lattice or end binding.

Highlights

Kinesins are a large superfamily of microtubule-associated molecular motors which can be grouped into 17 families based on the sequence of their characteristic motor domain (Lawrence et al, 2004; Wickstead & Gull, 2006)
The microtubule end-residence time for this variant was increased relative to wild-type Kinesin-1 (Table 1 and Figure 2b) but not to the same degree as the increase caused by introduction of the Kinesin-13 family specific residue at this position
To better understand microtubule end recognition by kinesins, we introduced Kinesin-13 family specific residues into the motor domain of a Kinesin-1 rkin430

Summary

| INTRODUCTION

Kinesins are a large superfamily of microtubule-associated molecular motors which can be grouped into 17 families based on the sequence of their characteristic motor domain (Lawrence et al, 2004; Wickstead & Gull, 2006). A key feature of the molecular mechanism of kinesins that regulate microtubule dynamics is the ability to recognise the microtubule end. This is demonstrated by an ability to remain at or near the microtubule end for extended times. The translocating activity and cargo carrying function of the Kinesin-1 family does not require the ability to recognise the microtubule end and this ability has not been detected for a Kinesin-1. Substitution of Kinesin-13 family specific residues from the α4-helix into equivalent positions in a Kinesin-1 confers the ability to distinguish the microtubule end from the lattice, such that the microtubule end-residence times of Kinesin mutants are increased several-fold

| RESULTS

| DISCUSSION

Findings

| MATERIALS AND METHODS