Biology subjects

Weijman, J. F.

Publications and source records attributed to Weijman, J. F..

5 recordsLinked to original sources

bioRxiv2025

Molecular mechanism for cargo-mediated initiation of kinesin-1 activation

Kinesin-1 is a dynamic heterotetrameric assembly of two heavy and two light chains (KHC and KLC) that mediates microtubule-based intracellular transport of many different cargoes. The complex adopts a compact, autoinhibited state that is activated by cargo-adaptor proteins containing specific short linear peptide motifs (SLiMs). These motifs interact with the tetratricopeptide repeat (TPR) domains of the KLCs. The mechanism coupling SLiM recognition to activation-associated conformational changes in the complex is unknown. Here we combine protein design, computational modelling, biophysical analysis, and electron microscopy to examine the structural and mechanistic consequences of SLiM binding to the KLC-TPR domain within the complete heterotetrameric holoenzyme. We show that coiled coil 1 (CC1) of the KHC docks KLC TPR domains in the autoinhibited complex, forming the shoulder feature observed in electron microscopy. Disrupting this interaction or binding an activating SLiM dislocates the TPR shoulder, freeing the motor domains and promoting transition between its closed, inactive, and open states. Opening the kinesin-1 complex facilitates binding to the microtubule-associated kinesin-1 cofactor, MAP7. Therefore, cargo-mediated dislocation of the TPR shoulder serves as a key initial step in kinesin-1 activation, allosterically linking cargo binding to motor dynamics.

biochemistry↗

bioRxiv2023

Roles for CEP170 in cilia function and dynein-2 assembly.

Primary cilia are essential eukaryotic organelles required for signalling and secretion. Dynein-2 is a microtubule-motor protein complex and is required for ciliogenesis via its role in facilitating retrograde intraflagellar transport from the cilia tip to the cell body. Dynein-2 must be assembled and loaded onto IFT-trains for entry into cilia for this process to occur but how dynein-2 is assembled at the base and how it is recycled back into a cilium remain poorly understood. Here, we identify Centrosomal Protein of 170 kDa (CEP170) as a dynein-2 interacting protein. We show that loss of CEP170 perturbs intraflagellar transport, Hedgehog signalling, and alters the stability of dynein-2 holoenzyme complex. Together, our data indicate a role for CEP170 in supporting cilia function and dynein-2 assembly. SummaryIntraflagellar transport is required for the function of primary cilia. In this work, we show that Centrosomal Protein 170 (CEP170) interacts with the IFT motor dynein-2 and loss of CEP170 causes defects in dynein-2 assembly and cilia function.

cell biology↗

bioRxiv2023

Allosteric regulation of a molecular motor through de novo protein design

Many enzymes are allosterically regulated. Our ability to manipulate these structural changes is limited. Here we install an allosteric switch into the kinesin-1 microtubule motor in vitro and in cells. Kinesin-1 is a heterotetramer that accesses open active and closed auto-inhibited states. The equilibrium between these centres on a flexible elbow within a complex coiled-coil architecture. We target the elbow to engineer a closed state that can be opened with a de novo designed peptide. The alternative states are modelled computationally and confirmed by biophysical measurements and electron microscopy. In cells, peptide-driven activation increases kinesin transport, demonstrating a primary role for conformational switching in regulating motor activity. The designs are enabled by our understanding of ubiquitous coiled-coil structures, opening possibilities for controlling other protein activities. One Sentence SummaryDe novo peptide and protein design are used to engineer an allosteric switch into kinesin-1 motors in vitro and directly in cells.

synthetic biology↗

bioRxiv2022

Molecular architecture of the autoinhibited kinesin-1 lambda particle

Despite continuing progress in kinesin enzyme mechanochemistry and emerging understanding of the cargo recognition machinery, it is not known how these functions are coupled and controlled by the alpha-helical coiled coils encoded by a large component of kinesin protein sequences. Here, we combine computational structure prediction with single-particle negative stain electron microscopy to reveal the coiled-coil architecture of heterotetrameric kinesin-1, in its compact state. An unusual flexion in the scaffold enables folding of the complex, bringing the kinesin heavy chain-light chain interface into close apposition with a tetrameric assembly formed from the region of the molecule previously assumed to be the folding hinge. This framework for autoinhibition is required to uncover how engagement of cargo and other regulatory factors drive kinesin-1 activation. Summary statementIntegration of computational structure prediction with electron microscopy reveals the coiled-coil architecture of the autoinhibited compact conformer of the microtubule motor, kinesin-1.

cell biology↗

bioRxiv2021

Molecular mechanism for kinesin-1 direct membrane recognition

The cargo-binding capabilities of cytoskeletal motor proteins have expanded during evolution through both gene duplication and alternative splicing. For the light chains of the kinesin-1 family of microtubule motors, this has resulted in an array of carboxy-terminal domain sequences of unknown molecular function. Here, combining phylogenetic analyses with biophysical, biochemical and cell biology approaches we identify a highly conserved membrane-induced curvature-sensitive amphipathic helix within this region of a newly defined subset of long kinesin light chain paralogues and splice isoforms. This helix mediates the direct binding of kinesin-1 to lipid membranes. Membrane binding requires specific anionic phospholipids and is important for kinesin-1 dependent lysosome positioning, a canonical activity that until now has been attributed exclusively the recognition of organelle-associated cargo adaptor proteins. This leads us to propose a new protein-lipid coincidence detection framework for kinesin-1 mediated organelle transport.

cell biology↗