{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"bioRxiv"}],"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T15:35:57Z","timestamp":1785425757628,"version":"3.56.0"},"posted":{"date-parts":[[2026,3,9]]},"group-title":"Cell Biology","reference-count":57,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2026,3,9]],"date-time":"2026-03-09T00:00:00Z","timestamp":1773014400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/www.biorxiv.org\/about\/FAQ#license"}],"funder":[{"award":["1R01AI184433"],"award-info":[{"award-number":["1R01AI184433"]}],"id":[{"id":"https:\/\/ror.org\/043z4tv69","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2026,3,9]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                <jats:p>\n                  The phylum Apicomplexa contains \u223c 6000 known species of unicellular eukaryotic parasites. A unifying feature among the apicomplexans is the apical complex, which varies in complexity in different lineages, but always contains an annulus (a.k.a. the apical polar ring) into which the minus ends of an array of cortical microtubules are embedded. In\n                  <jats:italic>Toxoplasma gondii,<\/jats:italic>\n                  the apical complex also includes the conoid, which contains several signaling and structural proteins critical for parasite motility. The conoid extends and retracts through the apical polar ring in a calcium-dependent manner. Here we report the identification of several new apical polar ring components, including APR9, which is highly conserved among the apicomplexans and their free-living relative\n                  <jats:italic>Chromera velia<\/jats:italic>\n                  . The loss of APR9 alone has only a moderate impact on the parasite lytic cycle. However, the knockout of both APR9 and KinesinA (another apical polar ring component) paralyzes parasite and drastically impairs invasion, egress and the lytic cycle. The double-knockout displays multiple subcellular abnormalities, including the formation of an apical actin concentration, impaired conoid extension, and significantly reduced secretion of a major adhesin (MIC2) upon stimulation with a calcium ionophore. These findings reveal that the apical polar ring plays a critical role in parasite motility and contributes to multiple subcellular processes.\n                <\/jats:p>","DOI":"10.64898\/2026.03.07.707822","type":"posted-content","created":{"date-parts":[[2026,3,9]],"date-time":"2026-03-09T09:25:23Z","timestamp":1773048323000},"source":"Crossref","is-referenced-by-count":0,"title":["The human parasite,\n                  <i>Toxoplasma gondii,<\/i>\n                  is paralyzed without two components of the apical polar ring"],"prefix":"10.64898","author":[{"given":"Jonathan Munera","family":"Lopez","sequence":"first","affiliation":[{"name":"Biodesign Center for Mechanisms of Evolution\/School of Life Sciences, Arizona State University, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Luisa F.","family":"Arias Padilla","sequence":"additional","affiliation":[{"name":"Biodesign Center for Mechanisms of Evolution\/School of Life Sciences, Arizona State University, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Isadonna F.","family":"Tengganu","sequence":"additional","affiliation":[{"name":"Biodesign Center for Mechanisms of Evolution\/School of Life Sciences, Arizona State University, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yan","family":"Hao","sequence":"additional","affiliation":[{"name":"Stowers Institute for Medical Research, Kansas City, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ying","family":"Zhang","sequence":"additional","affiliation":[{"name":"Stowers Institute for Medical Research, Kansas City, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Laurence","family":"Florens","sequence":"additional","affiliation":[{"name":"Stowers Institute for Medical Research, Kansas City, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"John M.","family":"Murray","sequence":"additional","affiliation":[{"name":"Biodesign Center for Mechanisms of Evolution\/School of Life Sciences, Arizona State University, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9778-7337","authenticated-orcid":false,"given":"Ke","family":"Hu","sequence":"additional","affiliation":[{"name":"Biodesign Center for Mechanisms of Evolution\/School of Life Sciences, Arizona State University, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"54368","reference":[{"key":"2026031108150967000_2026.03.07.707822v1.1","doi-asserted-by":"crossref","first-page":"1369","DOI":"10.12688\/f1000research.7924.1","article-title":"Recent advances in understanding apicomplexan parasites","volume":"5","year":"2016","journal-title":"F1000Res"},{"key":"2026031108150967000_2026.03.07.707822v1.2","doi-asserted-by":"publisher","DOI":"10.1016\/S1473-3099(14)70772-8"},{"key":"2026031108150967000_2026.03.07.707822v1.3","doi-asserted-by":"publisher","DOI":"10.2471\/BLT.12.111732"},{"key":"2026031108150967000_2026.03.07.707822v1.4","unstructured":"World-Health-Organization. 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