Biology subjects

O'Regan, L.

Publications and source records attributed to O'Regan, L..

5 recordsLinked to original sources

bioRxiv2026

Kinase-gated coincidence detection controls kinesin-driven lysosome transport

Kinesin motors drive long-range intracellular transport through coordinated cargo recognition and conformational autoregulation, yet the mechanisms that selectively control cargo engagement remain unclear. Here, we identify a phosphorylation-dependent gate on kinesin-1 activity mediated by the carboxy-terminal domain (CTD) of kinesin light chain 2 (KLC2). The KLC2 CTD is constitutively phosphorylated on multiple serine residues, suppressing membrane association via its amphipathic helix. We identify the NIMA-related kinase NEK10 as a KLC2-selective regulator of kinesin-1, restraining motor activation, cargo engagement, and lysosome transport; conversely, loss of NEK10 increases membrane association and, together with low-affinity adaptor interactions, promotes lysosome motility. These findings reveal a phosphorylation-regulated protein-lipid coincidence-detection mechanism - a kinesin-kinase code - that integrates adaptor binding with membrane cues to control kinesin-1-mediated transport and provide a mechanistic basis for understanding paralogue and isoform diversity in the kinesin-1 family.

cell biology↗

bioRxiv2025

NEK7 phosphorylation of cortactin modulates the migratory capacity of cells expressing EML4-ALK V3

EML4-ALK is a common oncogenic driver of non-small cell lung cancer. Distinct EML4-ALK variants cause different rates of disease progression, with patients expressing variant 3 (V3) exhibiting accelerated metastasis. Cells expressing EML4-ALK V3 develop a mesenchymal-like morphology and enhanced migration that is dependent on the NEK9 and NEK7 kinases. However, downstream substrates of these kinases relevant to these phenotypes are largely unknown. Here, we show that the actin-binding protein cortactin is phosphorylated by NEK7 within the F-actin-binding region (ABR) and that depletion of cortactin abrogates the morphological and migration phenotypes induced by EML4-ALK V3. Expression of constitutively active mutants of NEK9 or NEK7 causes similar cortactin-dependent morphological and migration changes. Cortactin co-localises with NEK7 and EML4-ALK V3 at branched filopodia-like extensions that are also generated upon expression of a cortactin protein with phospho-mimetic mutations in the ABR. In contrast, phospho-null mutations dissociate cortactin from F-actin. We propose that EML4-ALK V3 alters cell morphology and promotes directed cell migration by modulating the actin cytoskeleton via NEK7-mediated phosphorylation of cortactin within its ABR. SUMMARY STATEMENTNEK7 phosphorylates key residues of cortactin in its actin-binding repeat region to modulate the actin architecture and migration of cells driven by the EML4-ALK V3 - NEK9 - NEK7 pathway.

cell biology↗

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↗

bioRxiv2019

EML4-ALK V3 drives cell migration through NEK9 and NEK7 kinases in non-small-cell lung cancer

EML4-ALK is an oncogenic fusion present in [~]5% lung adenocarcinomas. However, distinct EML4-ALK variants differ in the length of the EML4 microtubule-associated protein encoded within the fusion and are associated with a poorly understood variability in disease progression and therapeutic response. Here, we show that EML4-ALK variant 3, which is linked to accelerated metastatic spread and worse patient outcome, causes microtubule stabilization, formation of extended cytoplasmic protrusions, loss of cell polarity and increased cell migration. Strikingly, this is dependent upon the NEK9 kinase that interacts with the N-terminal region of EML4. Overexpression of wild-type EML4, as well as constitutive activation of NEK9, also perturbs cell morphology and accelerates cell migration in a manner that requires the downstream kinase NEK7 but not ALK activity. Moreover, elevated NEK9 is associated in patients with EML4-ALK V3 expression, as well as reduced progression-free and overall survival. Hence, we propose that EML4-ALK V3 promotes microtubule stabilization through recruitment of NEK9 and NEK7 to increase cell migration and that this represents a novel actionable pathway that drives disease progression in lung cancer.

cancer biology↗

bioRxiv2018

Mitotic phosphorylation by Nek6 and Nek7 reduces microtubule affinity of EML4 to alter spindle dynamics and promote chromosome congression

EML4 is a microtubule-associated protein that promotes microtubule stability. We show here that EML4 is distributed as punctate foci along the microtubule lattice in interphase but exhibits reduced association with spindle microtubules in mitosis. Microtubule sedimentation and cryo-electron microscopy and 3D reconstruction reveal that EML4 binds via its basic N-terminal domain to the acidic C-terminal tails of - and {beta}-tubulin on the microtubule surface. The mitotic kinases Nek6 and Nek7 can phosphorylate EML4 N-terminal domain at S144 and S146 in vitro, and depletion of these kinases leads to increased EML4 binding to microtubules in mitosis. An S144A-S146A double mutant not only binds inappropriately to mitotic microtubules but also interferes with chromosome congression. Meanwhile, constitutive activation of Nek6 or Nek7 reduces EML4 association with interphase microtubules. Together, these data support a model in which Nek6 and Nek7-dependent phosphorylation promotes dissociation of EML4 from microtubules in mitosis thereby altering microtubule dynamics to enable chromosome congression.

cell biology↗