Biology subjects

Westlake, C. J.

Publications and source records attributed to Westlake, C. J..

4 recordsLinked to original sources

bioRxiv2025

The Dishevelled C-terminus interacts with the centrosomal protein Kizuna to regulate microtubule organization during ciliogenesis.

Microtubules (MTs) serve as dynamic scaffolds that support diverse cellular processes, including cell division, intracellular transport, and epithelial morphogenesis. In ciliated cells, MTs not only form the axonemal backbone of cilia but also work in tandem with actin to build an apical meshwork that anchors and orients basal bodies. However, the mechanisms regulating apical MT organization during ciliogenesis remain poorly understood. Here, we identify the centrosomal protein Kizuna (Kiz) as a critical regulator of apical MT architecture. Kiz interacts with the C-terminus of Dishevelled 2 (Dvl-C), inducing an open conformation and enabling the recruitment of Protein Kinase C delta (PKC{delta}) to stabilize the apical MT meshwork. This Dvl2-Kiz-PKC{delta} signaling axis is essential for ciliogenesis across multiple contexts, including the formation of primary cilia in the eye, multicilia in the mucociliary epidermis (MCE), and mono-motile cilia in the left-right organizer, the gastrocoel roof plate (GRP). These findings reveal a conserved molecular mechanism linking Dvl2 conformational dynamics to MT organization and highlight Kizuna as a key mediator coupling non-canonical Wnt signaling to ciliogenesis, left-right patterning, and the organization of the apical actin microtubule meshwork in ciliated cells of embryos.

developmental biology↗

bioRxiv2022

Intracellular connections between basal bodies promote the coordinated behavior of motile cilia

Hydrodynamic flow produced by multi-ciliated cells is critical for fluid circulation and cell motility. Hundreds of cilia beat with metachronal synchrony for fluid flow. Cilia-driven fluid flow produces extracellular hydrodynamic forces that cause neighboring cilia to beat in a synchronized manner. However, hydrodynamic coupling between neighboring cilia is not the sole mechanism that drives cilia synchrony. Cilia are nucleated by basal bodies (BBs) that link to each other and to the cells cortex via BB-associated appendages. The intracellular BB and cortical network is hypothesized to synchronize ciliary beating by transmitting cilia coordination cues. The extent of intracellular ciliary connections and the nature of these stimuli remain unclear. Moreover, how BB connections influence the dynamics of individual cilia has not been established. We show by FIB-SEM imaging that cilia are coupled both longitudinally and laterally in the ciliate Tetrahymena thermophila by the underlying BB and cortical cytoskeletal network. To visualize the behavior of individual cilia in live, immobilized Tetrahymena cells, we developed Delivered Iron Particle Ubiety Live Light-(DIPULL) microscopy. Quantitative and computer analyses of ciliary dynamics reveal that BB connections control ciliary waveform and coordinate ciliary beating. Loss of BB connections reduces cilia-dependent fluid flow forces. SummarySoh et al investigate whether intracellular connections between basal bodies control ciliary behavior in multi-ciliated cells. Using a Tetrahymena live cell immobilization technique to quantify ciliary dynamics, they show that inter-BB connections are required for effective ciliary waveform and coordinated ciliary beating that promotes fluid flow.

cell biology↗

bioRxiv2019

The Deubiquitinating Enzyme USP37 Stabilizes CHK1 to Promote the Cellular Response to Replication Stress

The deubiquitinating enzyme USP37 is known to contribute to timely S-phase onset. However, it is not clear if USP37 is essential beyond S-phase entry despite expression and activity of USP37 peaking within S-phase. Here, we determine that USP37-depleted cells exhibited altered S-phase kinetics and harbored increased levels of the replication stress and DNA damage markers {gamma}H2AX and 53BP1 in response to perturbed replication. Depletion of USP37 also reduced cellular proliferation and led to increased sensitivity to agents that induce replication stress. Underlying the increased sensitivity, we found that the checkpoint kinase CHK1 is destabilized in the absence of USP37, attenuating its function. We further demonstrated that USP37 deubquitinates and stabilizes CHK1. Our data contribute to an evolving understanding of UPS37 as a multifaceted regulator of genome regulation.

cell biology↗

bioRxiv2018

Genomic knockout of alms1 in zebrafish recapitulates Alstrom syndrome and provides insight into metabolic phenotypes

SCIENTIFIC ABSTRACTAlstrom syndrome is an autosomal recessive obesity ciliopathy caused by loss-of-function mutations in the ALMS1 gene. In addition to multi-organ dysfunction, such as cardiomyopathy, retinal degeneration, and renal dysfunction, the disorder is characterized by high rates of obesity, insulin resistance and early onset type 2 diabetes mellitus (T2DM). To investigate mechanisms linking disease phenotypes we generated a loss-of-function deletion of alms1 in the zebrafish using CRISPR/Cas9. We demonstrate conserved phenotypic effects including cardiac defects, retinal degeneration, and metabolic deficits that included propensity for obesity and fatty livers in addition to hyperinsulinemia and glucose response defects. Gene expression changes in {beta}-cells isolated from alms1-/- mutants revealed changes consistent with insulin hyper-secretion and glucose sensing failure, which were also identified in cultured murine {beta}-cells lacking Alms1. These data present a zebrafish model to assess etiology and new secretory pathway defects underlying Alstrom syndrome-associated metabolic phenotypes. Given the hyperinsulinemia and reduced glucose sensitivity in these animals we also propose the alms1 loss-of-function mutant as a monogenic model for studying T2DM phenotypes.\n\nAUTHOR SUMMARYThese data comprise a thorough characterization of a zebrafish model of Alstrom syndrome, a human obesity syndrome caused by loss-of-function deletions in a single gene, ALMS1. The high rates of obesity and insulin resistance found in these patients suggest this disorder as a single-gene model for Type 2 Diabetes Mellitus (T2DM), a disorder caused by a variety of environmental and genetic factors in the general population. We identify a propensity for obesity, excess lipid storage, loss of {beta}-cells in islets, and hyperinsulinemia in larval and adult stages of zebrafish alms1 mutants. We isolated {beta}-cells from the alms1 mutants and compared the gene expression profiles from RNASeq datasets to identify molecular pathways that may contribute to the loss of {beta}-cells and hyperinsulinemia. The increase in genes implicated in generalized pancreatic secretion, insulin secretion, and glucose transport suggest potential {beta}-cell exhaustion as a source of {beta}-cell loss and excess larval insulin. We propose this mutant as a new genetic tool for understanding the metabolic failures found in Type 2 Diabetes Mellitus.

genetics↗