Eirini Tsekitsidou

All Publications

• A second chance in science. Science (New York, N.Y.) Tsekitsidou, E. 2023; 382 (6671): 734

  View details for DOI 10.1126/science.adm7488

  View details for PubMedID 37943898

• Calcineurin associates with centrosomes and regulates cilia length maintenance. Journal of cell science Tsekitsidou, E., Wong, C. J., Ulengin-Talkish, I., Barth, A. I., Stearns, T., Gingras, A. C., Wang, J. T., Cyert, M. S. 2023

  Abstract

  Calcineurin, or PP2B, the Ca2+ and calmodulin-activated phosphatase and target of immunosuppressants, has many substrates and functions that remain undiscovered. By combining rapid proximity-dependent labeling with cell cycle synchronization, we mapped the spatial distribution of calcineurin in different cell cycle stages. While calcineurin-proximal proteins did not vary significantly between interphase and mitosis, calcineurin consistently associated with multiple centrosomal/ciliary proteins. These include POC5, which binds centrin in a Ca2+-dependent manner and is a component of the luminal scaffold that stabilizes centrioles. We show that POC5 contains a calcineurin substrate motif (PxIxIT-type) that mediates calcineurin binding in vivo and in vitro. Using indirect immunofluorescence and ultrastructure expansion microscopy, we demonstrate that calcineurin co-localizes with POC5 at the centriole, and further show that calcineurin inhibitors alter POC5 distribution within the centriole lumen. Our discovery that calcineurin directly associates with centriolar proteins highlights a role for Ca2+ and calcineurin signaling at these organelles. Calcineurin inhibition promotes primary cilia elongation without affecting ciliogenesis. Thus, Ca2+ signaling within cilia includes previously unknown functions for calcineurin in cilia length maintenance, a process frequently disrupted in ciliopathies.

  View details for DOI 10.1242/jcs.260353

  View details for PubMedID 37013443

• Systematic Discovery of Short Linear Motifs Decodes Calcineurin Phosphatase Signaling. Molecular cell Wigington, C. P., Roy, J. n., Damle, N. P., Yadav, V. K., Blikstad, C. n., Resch, E. n., Wong, C. J., Mackay, D. R., Wang, J. T., Krystkowiak, I. n., Bradburn, D. A., Tsekitsidou, E. n., Hong, S. H., Kaderali, M. A., Xu, S. L., Stearns, T. n., Gingras, A. C., Ullman, K. S., Ivarsson, Y. n., Davey, N. E., Cyert, M. S. 2020

  Abstract

  Short linear motifs (SLiMs) drive dynamic protein-protein interactions essential for signaling, but sequence degeneracy and low binding affinities make them difficult to identify. We harnessed unbiased systematic approaches for SLiM discovery to elucidate the regulatory network of calcineurin (CN)/PP2B, the Ca2+-activated phosphatase that recognizes LxVP and PxIxIT motifs. In vitro proteome-wide detection of CN-binding peptides, in vivo SLiM-dependent proximity labeling, and in silico modeling of motif determinants uncovered unanticipated CN interactors, including NOTCH1, which we establish as a CN substrate. Unexpectedly, CN shows SLiM-dependent proximity to centrosomal and nuclear pore complex (NPC) proteins-structures where Ca2+ signaling is largely uncharacterized. CN dephosphorylates human and yeast NPC proteins and promotes accumulation of a nuclear transport reporter, suggesting conserved NPC regulation by CN. The CN network assembled here provides a resource to investigate Ca2+ and CN signaling and demonstrates synergy between experimental and computational methods, establishing a blueprint for examining SLiM-based networks.

  View details for DOI 10.1016/j.molcel.2020.06.029

  View details for PubMedID 32645368

• A novel quantitative real-time PCR diagnostic assay for seal heartworm (Acanthocheilonema spirocauda) provides evidence for possible infection in the grey seal (Halichoerus grypus) INTERNATIONAL JOURNAL FOR PARASITOLOGY-PARASITES AND WILDLIFE Keroack, C. D., Williams, K. M., Fessler, M. K., DeAngelis, K. E., Tsekitsidou, E., Tozloski, J. M., Williams, S. A. 2018; 7 (2): 147–54

  Abstract

  The distinct evolutionary pressures faced by Pinnipeds have likely resulted in strong coevolutionary ties to their parasites (Leidenberger et al., 2007). This study focuses on the phocid seal filarial heartworm species Acanthocheilonema spirocauda. A. spirocauda is known to infect a variety of phocid seals, but does not appear to be restricted to a single host species (Measures et al., 1997; Leidenberger et al., 2007; Lehnert et al., 2015). However, to date, seal heartworm has never been reported in grey seals (Halichoerus grypus) (Measures et al., 1997; Leidenberger et al., 2007; Lehnert et al., 2015). The proposed vector for seal heartworm is Echinophthirius horridus, the seal louse. Seal lice are known to parasitize a wide array of phocid seal species, including the grey seal. With the advent of climate change, disease burden is expected to increase across terrestrial and marine mammals (Harvell et al., 2002). Accordingly, increased prevalence of seal heartworm has recently been reported in harbor seals (Phoca vitulina) (Lehnert et al., 2015). Thus, the need for improved, rapid, and cost-effective diagnostics is urgent. Here we present the first A. spirocauda-specific rapid diagnostic test (a quantitative real-time PCR assay), based on a highly repetitive genomic DNA repeat identified using whole genome sequencing and subsequent bioinformatic analysis. The presence of an insect vector provides the opportunity to develop a multifunctional diagnostic tool that can be used not only to detect the parasite directly from blood or tissue specimens, but also as a molecular xenomonitoring (XM) tool that can be used to assess the epidemiological profile of the parasite by screening the arthropod vector. Using this assay, we provide evidence for the first reported case of seal heartworm in a grey seal.

  View details for DOI 10.1016/j.ijppaw.2018.04.001

  View details for Web of Science ID 000438781400005

  View details for PubMedID 29988808

  View details for PubMedCentralID PMC6031957