Biology subjects

Junker, A. D.

Publications and source records attributed to Junker, A. D..

3 recordsLinked to original sources

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↗

bioRxiv2021

Plastic cell morphology changes during dispersal

Dispersal is the movement of organisms from one habitat to another that potentially results in gene flow. It is often found to be plastic, allowing organisms to adjust dispersal movements depending on environmental conditions. A fundamental aim in ecology is to understand the determinants underlying dispersal and its plasticity. We utilized 22 strains of the ciliate Tetrahymena thermophila to determine if different phenotypic dispersal strategies co-exist within a species and which mechanisms underlie this variability. We quantified the cell morphologies impacting cell motility and dispersal. Distinct differences in innate cellular morphology and dispersal rates were detected, but no universally utilized combinations of morphological parameters correlate with dispersal. Rather, multiple distinct and plastic morphological changes impact cilia-dependent motility during dispersal, especially in proficient dispersing strains facing challenging environmental conditions. Combining ecology and cell biology experiments, we show that dispersal can be promoted through a panel of plastic motility-associated changes to cell morphology and motile cilia. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=152 SRC="FIGDIR/small/448130v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@1aad069org.highwire.dtl.DTLVardef@158adbdorg.highwire.dtl.DTLVardef@f6570forg.highwire.dtl.DTLVardef@cdc249_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LITetrahymena thermophila exhibits intra-specific diversity in morphology and dispersal. C_LIO_LICell motility behavior during dispersal changes with cilia length and cell shape. C_LIO_LICells from proficient dispersing strains transiently change basal body and cilia position. C_LIO_LIStarvation-induced dispersal triggers increased basal body and cilia density and caudal cilium formation in rapid-swimming cells. C_LI

cell biology↗

bioRxiv2019

Microtubule glycylation promotes basal body attachment to the cell cortex

Motile cilia generate directed hydrodynamic flow that is important for the motility of cells and extracellular fluids. To optimize directed hydrodynamic flow, motile cilia are organized and oriented into a polarized array. Basal bodies (BB) nucleate and position motile cilia at the cell cortex. Cytoplasmic BB-associated microtubules are conserved structures that extend from BBs. Using the ciliate, Tetrahymena thermophila, combined with EM-tomography and light microscopy, we show that BB-appendage microtubules assemble coincident with new BB assembly and are attached to the cell cortex. These BB-appendage microtubules are specifically marked with post translational modifications of tubulin, including glycylation. Mutations that prevent glycylation shorten BB-appendage microtubules and disrupt BB positioning and cortical attachment. Consistent with the attachment of BB-appendage microtubules to the cell cortex for BB positioning, mutations that disrupt the cellular cortical cytoskeleton similarly disrupt the cortical attachment and positioning of BBs. In summary, BB-appendage microtubules promote the organization of ciliary arrays through attachment to the cell cortex.\n\nSUMMARY STATEMENTBasal bodies position motile cilia at the cell cortex. This study finds tubulin glycylation to promote BB-associated microtubule elongation and structural attachment of basal bodies to the cells cortical cytoskeleton.

cell biology↗