The light chains of kinesin-1 are autoinhibited

Abstract

The light chains (KLCs) of the microtubule motor kinesin-1 bind cargoes and regulate its activity. Through their tetratricopeptide repeat domain (KLC TPR ), they can recognize short linear peptide motifs found in many cargo proteins characterized by a central tryptophan flanked by aspartic/glutamic acid residues (W-acidic). Using a fluorescence resonance energy transfer biosensor in combination with X-ray crystallographic, biochemical, and biophysical approaches, we describe how an intramolecular interaction between the KLC2 TPR domain and a conserved peptide motif within an unstructured region of the molecule, partly occludes the W-acidic binding site on the TPR domain. Cargo binding displaces this interaction, effecting a global conformational change in KLCs resulting in a more extended conformation. Thus, like the motor-bearing kinesin heavy chains, KLCs exist in a dynamic conformational state that is regulated by self-interaction and cargo binding. We propose a model by which, via this molecular switch, W-acidic cargo binding regulates the activity of the holoenzyme.kinesin | KLC | TPR domain | microtubule motor | cytoskeleton

SKIP controls lysosome positioning using a composite kinesin-1 heavy and light chain-binding domain

“…Measurements were performed on a Horiba Fluoromax-4 spectrofluorometer as described previously (Yip et al, 2016). …”

Structural basis for isoform-specific kinesin-1 recognition of Y-acidic cargo adaptors

“…The partial separation of Y-acidic and W-acidic binding sites on KLC TPR has also a possible important functional consequence. We have solved previously the 4 Å-resolution structure of KLC2 extTPR , an extended TPR featuring the conserved LFP-acidic region Nterminal to the KLC TPR domain that contributes to kinesin-1 inhibition ( Figure 1A) (Yip et al, 2016). In this structure the KLC2 TPR domain is in its 'open' (ligand-free) conformation and we could model a stretch five poly-Ala residues between helices α1, α3, α5 that likely defines the general location of the intramolecular LFP-acidic region.…”

“…At the molecular level kinesin-1 is a tetramer consisting of two ATP-dependent motor-bearing heavy chains (KHCs) and two light chains (KLCs) that in mammalian cells are encoded by three (Kif5A-C) and four (KLC1-4) closely related genes, respectively, with distinct cell and tissue expression profiles. When not engaged in active transport, kinesin-1 is maintained in an autoinhibited state resulting from an intramolecular interaction in which the C-terminus of a single KHC tail binds at the N-terminal motor dimer interface autoinhibited state, and is likely important in cargo-driven activation (Yip et al, 2016).…”

Decreased kinesin-1 mitigates NMDA-induced exicitotoxicity and ischemia-evoked neurodegeneration

“…Moreover, suppressing Kif5b expression, particularly by disrupting the Kif5b-GluN2B interaction, might open new therapeutic avenues. As the structure for kinesin-1 cargo binding motif has been resolved (Pernigo, Lamprecht et al, 2013, Yip, Pernigo et al, 2016, it would be tempting to resolve the structure for kinesin-1-GluN2B complex and use this structure as the basis to predict or design molecules that could halt extrasynaptic NMDAR mediated neurodegeneration. As such an approach would mimic intrinsic changes induced by brief and beneficial stimulations, it might be tolerated by brain and thus minimize potential side effects.…”