{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,15]],"date-time":"2026-06-15T14:41:41Z","timestamp":1781534501055,"version":"3.54.5"},"reference-count":36,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2022,5,31]],"date-time":"2022-05-31T00:00:00Z","timestamp":1653955200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001704","name":"European Society of Clinical Microbiology and Infectious Diseases","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100001704","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UIDP\/04378\/2020, UIDB\/04378\/2020, LA\/P\/0140\/2020"],"award-info":[{"award-number":["UIDP\/04378\/2020, UIDB\/04378\/2020, LA\/P\/0140\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Cell. Infect. Microbiol."],"abstract":"<jats:p><jats:italic>Legionella pneumophila<\/jats:italic> is an accidental human pathogen that causes the potentially fatal Legionnaires\u2019 disease, a severe type of pneumonia. The main virulence mechanism of <jats:italic>L. pneumophila<\/jats:italic> is a Type 4B Secretion System (T4SS) named Icm\/Dot that transports effector proteins into the host cell cytosol. The concerted action of effectors on several host cell processes leads to the formation of an intracellular Legionella-containing vacuole that is replication competent and avoids phagolysosomal degradation. To date over 300 Icm\/Dot substrates have been identified. In this study, we searched the genome of a <jats:italic>L. pneumophila<\/jats:italic> strain (Pt\/VFX2014) responsible for the second largest <jats:italic>L. pneumophila<\/jats:italic> outbreak worldwide (in Vila Franca de Xira, Portugal, in 2014) for genes encoding potential novel Icm\/Dot substrates. This strain Pt\/VFX2014 belongs to serogroup 1 but phylogenetically segregates from all other serogroup 1 strains previously sequenced, displaying a unique mosaic genetic backbone. The ability of the selected putative effectors to be delivered into host cells by the T4SS was confirmed using the TEM-1 \u03b2-lactamase reporter assay. Two previously unknown Icm\/Dot effectors were identified, VFX05045 and VFX10045, whose homologs Lpp1450 and Lpp3070 in clinical strain <jats:italic>L. pneumophila<\/jats:italic> Paris were also confirmed as T4SS substrates. After delivery into the host cell cytosol, homologs VFX05045\/Lpp1450 remained diffused in the cell, similarly to Lpp3070. In contrast, VFX10045 localized to the host cell nucleus. To understand how VFX10045 and Lpp3070 (94% of identity at amino acid level) are directed to distinct sites, we carried out a comprehensive site-directed mutagenesis followed by analyses of the subcellular localization of the mutant proteins. This led to the delineation of region in the C-terminal part (residues 380 to 534) of the 583 amino acid-long VFX10045 as necessary and sufficient for nuclear targeting and highlighted the fundamental function of the VFX10045-specific R440 and I441 residues in this process. These studies revealed a strain-specific nucleotropism for new effector VFX10045\/Lpp3070, which anticipates distinct functions between these homologs.<\/jats:p>","DOI":"10.3389\/fcimb.2022.864626","type":"journal-article","created":{"date-parts":[[2022,6,1]],"date-time":"2022-06-01T05:05:46Z","timestamp":1654059946000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":5,"title":["A Search for Novel\u00a0Legionella pneumophila\u00a0Effector Proteins Reveals a Strain Specific Nucleotropic Effector"],"prefix":"10.3389","volume":"12","author":[{"given":"In\u00eas P.","family":"Monteiro","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sofia","family":"Sousa","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"V\u00edtor","family":"Borges","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paulo","family":"Gon\u00e7alves","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jo\u00e3o Paulo","family":"Gomes","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lu\u00eds Jaime","family":"Mota","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Irina S.","family":"Franco","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2022,5,31]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.3389\/fcell.2019.00390","article-title":"Methylomic Changes of Autophagy-Related Genes by Legionella Effector Lpg2936 in Infected Macrophages","volume":"7","author":"Abd El Maksoud","year":"2020","journal-title":"Front. 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