@article{bellingham-johnstun_tyree_martinez-baird_thorn_laplante_2023, title={Actin-Microtubule Crosstalk Imparts Stiffness to the Contractile Ring in Fission Yeast}, volume={12}, ISSN={["2073-4409"]}, DOI={10.3390/cells12060917}, abstractNote={Actin–microtubule interactions are critical for cell division, yet how these networks of polymers mutually influence their mechanical properties and functions in live cells remains unknown. In fission yeast, the post-anaphase array (PAA) of microtubules assembles in the plane of the contractile ring, and its assembly relies on the Myp2p-dependent recruitment of Mto1p, a component of equatorial microtubule organizing centers (eMTOCs). The general organization of this array of microtubules and the impact on their physical attachment to the contractile ring remain unclear. We found that Myp2p facilitates the recruitment of Mto1p to the inner face of the contractile ring, where the eMTOCs polymerize microtubules without their direct interaction. The PAA microtubules form a dynamic polygon of Ase1p crosslinked microtubules inside the contractile ring. The specific loss of PAA microtubules affects the mechanical properties of the contractile ring of actin by lowering its stiffness. This change in the mechanical properties of the ring has no measurable impact on cytokinesis or on the anchoring of the ring. Our work proposes that the PAA microtubules exploit the contractile ring for their assembly and function during cell division, while the contractile ring may receive no benefit from these interactions.}, number={6}, journal={CELLS}, author={Bellingham-Johnstun, Kimberly and Tyree, Zoe L. and Martinez-Baird, Jessica and Thorn, Annelise and Laplante, Caroline}, year={2023}, month={Mar} }
 @article{bellingham-johnstun_thorn_belmonte_laplante_2023, title={Microtubule competition and cell growth recenter the nucleus after anaphase in fission yeast}, volume={34}, ISSN={["1939-4586"]}, DOI={10.1091/mbc.E23-01-0034}, abstractNote={Cells actively position their nuclei based on their activity. In fission yeast, microtubule-dependent nuclear centering is critical for symmetrical cell division. After spindle disassembly at the end of anaphase, the nucleus recenters over an ∼90-min period, approximately half of the duration of the cell cycle. Live-cell and simulation experiments support the cooperation of two distinct microtubule competition mechanisms in the slow recentering of the nucleus. First, a push–push mechanism acts from spindle disassembly to septation and involves the opposing actions of the mitotic spindle pole body microtubules that push the nucleus away from the ends of the cell, while a postanaphase array of microtubules baskets the nucleus and limits its migration toward the division plane. Second, a slow-and-grow mechanism slowly centers the nucleus in the newborn cell by a combination of microtubule competition and asymmetric cell growth. Our work underlines how intrinsic properties of microtubules differently impact nuclear positioning according to microtubule network organization and cell size.}, number={8}, journal={MOLECULAR BIOLOGY OF THE CELL}, author={Bellingham-Johnstun, Kimberly and Thorn, Annelise and Belmonte, Julio M. and Laplante, Caroline}, year={2023}, month={Jul} }
 @article{bellingham-johnstun_commer_levesque_tyree_laplante_2022, title={Imp2p forms actin-dependent clusters and imparts stiffness to the contractile ring}, volume={33}, ISSN={["1939-4586"]}, DOI={10.1091/mbc.E22-06-0221}, abstractNote={The contractile ring must anchor to the plasma membrane and cell wall to transmit its tension. F-BAR domain containing proteins including Imp2p and Cdc15p in fission yeast are likely candidate anchoring proteins based on their mutant phenotypes. Cdc15p is a node component, links the actin bundle to the plasma membrane, recruits Bgs1p to the division plane, prevents contractile ring sliding, and contributes to the stiffness of the contractile ring. Less is known about Imp2p. We found that similarly to Cdc15p, Imp2p contributes to the stiffness of the contractile ring and assembles into protein clusters. Imp2p clusters contain approximately eight Imp2p dimers and depend on the actin network for their stability at the division plane. Importantly, Imp2p and Cdc15p reciprocally affect the amount of each other in the contractile ring, indicating that the two proteins influence each other during cytokinesis, which may partially explain their similar phenotypes.}, number={14}, journal={MOLECULAR BIOLOGY OF THE CELL}, author={Bellingham-Johnstun, Kimberly and Commer, Blake and Levesque, Brie and Tyree, Zoe L. and Laplante, Caroline}, year={2022}, month={Dec} }
 @article{moshtohry_bellingham-johnstun_elting_laplante_2022, title={Laser ablation reveals the impact of Cdc15p on the stiffness of the contractile ring}, volume={33}, ISSN={["1939-4586"]}, DOI={10.1091/mbc.E21-10-0515}, abstractNote={The mechanics that govern the constriction of the contractile ring remain poorly understood yet are critical to understanding the forces that drive cytokinesis. We used laser ablation in fission yeast cells to unravel these mechanics focusing on the role of Cdc15p as a putative anchoring protein. Our work shows that the severed constricting contractile ring recoils to a finite point leaving a gap that can heal if less than ∼1 µm. Severed contractile rings in Cdc15p-depleted cells exhibit an exaggerated recoil, which suggests that the recoil is limited by the anchoring of the ring to the plasma membrane. Based on a physical model of the severed contractile ring, we propose that Cdc15p impacts the stiffness of the contractile ring more than the viscous drag.}, number={6}, journal={MOLECULAR BIOLOGY OF THE CELL}, author={Moshtohry, Mohamed and Bellingham-Johnstun, Kimberly and Elting, Mary Williard and Laplante, Caroline}, year={2022}, month={May} }
 @article{amaral_mcqueen_bellingham-johnstun_poston_darville_nagarajan_laplante_kaser_2021, title={Host-Pathogen Interactions of Chlamydia trachomatis in Porcine Oviduct Epithelial Cells}, volume={10}, ISSN={["2076-0817"]}, url={https://www.mdpi.com/2076-0817/10/10/1270}, DOI={10.3390/pathogens10101270}, abstractNote={Chlamydia trachomatis (Ct) causes the most prevalent bacterial sexually transmitted disease leading to ectopic pregnancy and infertility. Swine not only have many similarities to humans, but they are also susceptible to Ct. Despite these benefits and the ease of access to primary tissue from this food animal, in vitro research in swine has been underutilized. This study will provide basic understanding of the Ct host–pathogen interactions in porcine oviduct epithelial cells (pOECs)—the counterparts of human Fallopian tube epithelial cells. Using NanoString technology, flow cytometry, and confocal and transmission-electron microscopy, we studied the Ct developmental cycle in pOECs, the cellular immune response, and the expression and location of the tight junction protein claudin-4. We show that Ct productively completes its developmental cycle in pOECs and induces an immune response to Ct similar to human cells: Ct mainly induced the upregulation of interferon regulated genes and T-cell attracting chemokines. Furthermore, Ct infection induced an accumulation of claudin-4 in the Ct inclusion with a coinciding reduction of membrane-bound claudin-4. Downstream effects of the reduced membrane-bound claudin-4 expression could potentially include a reduction in tight-junction expression, impaired epithelial barrier function as well as increased susceptibility to co-infections. Thereby, this study justifies the investigation of the effect of Ct on tight junctions and the mucosal epithelial barrier function. Taken together, this study demonstrates that primary pOECs represent an excellent in vitro model for research into Ct pathogenesis, cell biology and immunity.}, number={10}, journal={PATHOGENS}, publisher={MDPI AG}, author={Amaral, Amanda F. and McQueen, Bryan E. and Bellingham-Johnstun, Kimberly and Poston, Taylor B. and Darville, Toni and Nagarajan, Uma M. and Laplante, Caroline and Kaser, Tobias}, year={2021}, month={Oct} }
 @article{bellingham-johnstun_anders_ravi_bruinsma_laplante_2021, title={Molecular organization of cytokinesis node predicts the constriction rate of the contractile ring}, volume={220}, ISSN={["1540-8140"]}, DOI={10.1083/jcb.202008032}, abstractNote={The function of the contractile ring during cytokinesis depends on its molecular organization. This study uses single-molecule localization microscopy in live fission yeast cells to show that distinct molecular organizations of the myosin-II Myo2p correlate with different constriction rates of the contractile ring.}, number={3}, journal={JOURNAL OF CELL BIOLOGY}, author={Bellingham-Johnstun, Kimberly and Anders, Erica Casey and Ravi, John and Bruinsma, Christina and Laplante, Caroline}, year={2021}, month={Mar} }