{"id":21590,"date":"2023-09-13T10:40:11","date_gmt":"2023-09-13T14:40:11","guid":{"rendered":"http:\/\/www.bumc.bu.edu\/ppb\/?page_id=21590"},"modified":"2023-09-13T10:41:02","modified_gmt":"2023-09-13T14:41:02","slug":"the-bullitt-lab","status":"publish","type":"page","link":"https:\/\/www.bumc.bu.edu\/ppb\/the-bullitt-lab\/","title":{"rendered":"The Bullitt Lab"},"content":{"rendered":"<p><strong><span style=\"color: #ff6600;\">Working Together to\u00a0Promote an Inclusive Community<\/span><br \/>\n<strong>I SUPPORT EQUITY AND INCLUSION, AND THE BLACK LIVES MATTER MOVEMENT<\/strong><\/strong><\/p>\n<h4>Bullitt Lab Research<\/h4>\n<h5 style=\"text-align: center;\">Protein Structure Facilitates Function<br \/>\nUsing Electron Microscopy and Quantitative Image Analysis to see how Macromolecular Assemblies Work<\/h5>\n<p>Structural studies of biological macromolecular assemblies are providing a deeper understanding of cellular function. In our laboratory, we utilize electron microscopy and image reconstruction to investigate questions about:<\/p>\n<ul>\n<li>how adhesion pili aid pathogenic bacterial survival<\/li>\n<li>how viruses impact cellular processes<\/li>\n<li>how the type III secretion system is assembled, leading to secretion of toxins<\/li>\n<\/ul>\n<h5 style=\"text-align: justify;\">BACTERIAL ADHESION PILI<\/h5>\n<p><strong>YouTube: \u00a0the role of basic research in developing a vaccine against Traveler&#8217;s Diarrhea:<\/strong> <a href=\"https:\/\/www.youtube.com\/watch?v=MK_4RgCEz7Y&amp;feature=youtu.be\"><strong>Vaccines from basic research<\/strong><\/a><\/p>\n<figure id=\"attachment_20788\" aria-describedby=\"caption-attachment-20788\" style=\"width: 310px\" class=\"wp-caption alignright\"><img loading=\"lazy\" src=\"\/ppb\/files\/2023\/05\/ecoli_18hr_001-300x300.jpg\" alt=\"\" width=\"300\" height=\"300\" class=\"wp-image-20788 size-medium\" srcset=\"https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/ecoli_18hr_001-300x300.jpg 300w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/ecoli_18hr_001.jpg 1024w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/ecoli_18hr_001-150x150.jpg 150w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/ecoli_18hr_001-768x768.jpg 768w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/ecoli_18hr_001-550x550.jpg 550w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/ecoli_18hr_001-710x710.jpg 710w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/ecoli_18hr_001-600x600.jpg 600w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/ecoli_18hr_001-100x100.jpg 100w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><figcaption id=\"caption-attachment-20788\" class=\"wp-caption-text\">Pathogenic bacteria express pili (also called \u2018fimbriae\u2019) on their surface for adhesion to their target cell: Shown here is an enterotoxigenic E. coli (ETEC) expressing CFA\/I pili. Bacterium is ~ 1 \u00b5M by 3 \u00b5M, and pili are helical filaments ~8 nm in diameter and over 1 \u00b5M long<\/figcaption><\/figure>\n<p style=\"text-align: justify;\">Fibers on the surfaces of many pathogenic bacteria can overextend like a toy Slinky, whereas homologous proteins on bacteria that cause pneumonia, ear infections, and meningitis assemble into a 3-stranded rope-like fibers (blue). In collaboration with Dr. Magnus Andersson&#8217;s lab at Ume\u00e5 University in Ume\u00e5 Sweden and Dr. Joseph Baker&#8217;s lab at the College of New Jersey we have shown that the forces required for unwinding pili (also called &#8216;fimbriae&#8217;) are specific for the pilus-type, and thus vary with the microenvironment expected to be encountered. For example, CFA\/I pili on diarrhea-causing intestinal bacteria unwind at less than one-third the force required to unwind P-pili expressed on urinary tract infection bacteria.<\/p>\n<p style=\"text-align: justify;\">Our cryo-electron microscopy (cryo-EM) results now show the structure of CFA\/I pili at 3.5 A resolution, previously published at 4.3 A resolution in<br \/>\nIUCrJ (2019) \u00a06, 815\u2013821,<\/p>\n<p style=\"text-align: justify;\">https:\/\/doi.org\/10.1107\/S2052252519007966<\/p>\n<p style=\"text-align: justify;\">As more bacteria become resistant to antibiotics, it is essential to develop novel approaches for prevention and treatment of infection. Structural studies are vital for discovering clues to how bacteria bind, and how they remain attached while the host is trying to remove them. We are examining the architecture of bacterial adhesion pili and investigating small molecules that disrupt their assembly and\/or function. We see that pilin subunits must rotate to form a helical filament, after exiting linearly from the bacterial surface.<\/p>\n<figure id=\"attachment_20789\" aria-describedby=\"caption-attachment-20789\" style=\"width: 234px\" class=\"wp-caption alignleft\"><img loading=\"lazy\" src=\"\/ppb\/files\/2023\/05\/Figure1_CFA1_IUCrJ_Apr2019_v2-474x636-1-224x300.jpg\" alt=\"\" width=\"224\" height=\"300\" class=\"wp-image-20789 size-medium\" srcset=\"https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/Figure1_CFA1_IUCrJ_Apr2019_v2-474x636-1-224x300.jpg 224w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/Figure1_CFA1_IUCrJ_Apr2019_v2-474x636-1.jpg 474w\" sizes=\"(max-width: 224px) 100vw, 224px\" \/><figcaption id=\"caption-attachment-20789\" class=\"wp-caption-text\">CFA\/I pili at 4.3 Angstrom resolution. IUCRJ. https:\/\/doi.org\/10.1107\/S2052252519007966<\/figcaption><\/figure>\n<figure id=\"attachment_20790\" aria-describedby=\"caption-attachment-20790\" style=\"width: 454px\" class=\"wp-caption alignright\"><img loading=\"lazy\" src=\"\/ppb\/files\/2023\/05\/CfaBBB_into_cryoEM_v2-650x439-1-444x300.png\" alt=\"\" width=\"444\" height=\"300\" class=\"wp-image-20790 size-medium\" srcset=\"https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/CfaBBB_into_cryoEM_v2-650x439-1-444x300.png 444w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/CfaBBB_into_cryoEM_v2-650x439-1.png 650w\" sizes=\"(max-width: 444px) 100vw, 444px\" \/><figcaption id=\"caption-attachment-20790\" class=\"wp-caption-text\">The linearly connected pilin subunits (blue) must rotate after exiting the bacterium, to coil into helical pili filaments<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_20793\" aria-describedby=\"caption-attachment-20793\" style=\"width: 660px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" src=\"\/ppb\/files\/2023\/05\/Pilins_sm_helix_and_S-S_bonds_v8-650x220-1.png\" alt=\"\" width=\"650\" height=\"220\" class=\"wp-image-20793 size-full\" \/><figcaption id=\"caption-attachment-20793\" class=\"wp-caption-text\">In some pili, a small helix uncoils to relieve even more load from the pilus\/target interaction. This helix is absent in ETEC pili Class 5, and present in ETEC Class 1.<\/figcaption><\/figure>\n<p style=\"text-align: justify;\"><em><strong>Selected Publications<\/strong><\/em><\/p>\n<p style=\"text-align: justify;\"><strong>Bullitt, E<\/strong>., L. Makowski <em>(1995). Structural polymorphism of bacterial adhesion pili. Nature 373:164-167. PMID: 7816100<\/em><\/p>\n<p><span style=\"text-decoration: underline;\">Brown JW, Badahdah A,<\/span> Iticovici M, Vickers TJ, Alvarado DM, Helmerhorst EJ, Oppenheim FG, Mills JC, Ciorba MA, Fleckenstein JM, <strong>Bullitt E<\/strong><em> (2018). A Role for Salivary Peptides in the Innate Defense Against Enterotoxigenic Escherichia coli.<\/em><span>\u00a0<\/span><em>J Infect Dis<\/em>. 2018 217:1435-1441. doi: 10.1093\/infdis\/jiy032. PMID 29528423.<span>\u00a0 <\/span><span>\u00a0<\/span>PMC5894089<\/p>\n<p>Baker JL, Dahlberg T, <strong>Bullitt E<\/strong>, Andersson M <em>(2021)<\/em>. <em>Impact of an alpha helix and a cysteine-cysteine disulfide bond on the resistance of bacterial adhesion pili to stress.\u00a0 <\/em><span>\u00a0<\/span><em>Proc Natl Acad Sci U S A<\/em>. 118:e2023595118. doi: 10.1073\/pnas.2023595118. PMID 34011607.<span>\u00a0 <\/span><span>\u00a0<\/span>PMC8166124<\/p>\n<h5 style=\"text-align: justify;\"><strong><br style=\"clear: both;\" \/>CHANGES TO CELLS DURING VIRUS REPLICATION<\/strong><\/h5>\n<p style=\"text-align: justify;\">Extracellular vesicles secreted from virus-infected cells contain components necessary to begin virus replication quickly, including viral RNA and proteins as well as host proteins.<\/p>\n<p style=\"text-align: justify;\"><span style=\"text-decoration: underline;\">Yang JE, Rossignol ED<\/span>, Chang D, Zaia J, Forrester I, <span style=\"text-decoration: underline;\">Raja K<\/span>, Winbigler H, Nicastro D, Jackson WT, <strong>Bullitt E<\/strong>\u00a0(2020). <em> Complexity and ultrastructure of infectious extracellular vesicles from cells infected by non-enveloped virus. Sci Rep. <\/em>10:7939. doi: 10.1038\/s41598-020-64531-1. PMID 32409751. PMCID: PMC7224179<\/p>\n<figure id=\"attachment_20802\" aria-describedby=\"caption-attachment-20802\" style=\"width: 246px\" class=\"wp-caption alignright\"><img loading=\"lazy\" src=\"\/ppb\/files\/2023\/05\/CellularMicro_v19_i8_cover_2017_reformat-500x636-1-236x300.png\" alt=\"\" width=\"236\" height=\"300\" class=\"wp-image-20802 size-medium\" srcset=\"https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/CellularMicro_v19_i8_cover_2017_reformat-500x636-1-236x300.png 236w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/CellularMicro_v19_i8_cover_2017_reformat-500x636-1.png 500w\" sizes=\"(max-width: 236px) 100vw, 236px\" \/><figcaption id=\"caption-attachment-20802\" class=\"wp-caption-text\">Zika virus transforms the endoplasmic reticulum (ER) of its target cell to provide a site for viral replication.<\/figcaption><\/figure>\n<p style=\"text-align: justify;\">We are using our expertise from studies on poliovirus replication, we have multiple collaborators at BUSM for studies on Zika Virus, SARS-CoV2, and filoviruses.<\/p>\n<p><u>Rossignol ED<\/u>, Peters KN, Connor JH, <strong>Bullitt E<\/strong>\u00a0 (2017). \u00a0<em>Zika virus induced cellular remodelling.\u00a0 <\/em><span>\u00a0<\/span><em>Cell Microbiol<\/em>. 19:10.1111\/cmi.12740. doi: 10.1111\/cmi.12740. PMID 28318141.<span>\u00a0 <\/span><span>\u00a0<\/span>PMC5561415<\/p>\n<p style=\"text-align: justify;\">In collaboration with Dr. Karla Kirkegaard&#8217;s lab at Stanford University we have shown that\u00a0&#8220;Zombie&#8221; 3Dpol protein (dead active site) can support assembly of oligomers and restore replication when the wild type protein concentration is too low to do so.<\/p>\n<p style=\"text-align: justify;\">Spagnolo, J.F., <span style=\"text-decoration: underline;\">E. Rossignol<\/span>, <strong>E. Bullitt<\/strong>, K. Kirkegaard (2010).<em> Enzymatic and non-enzymatic functions of viral RNA-dependent RNA polymerases within oligomeric arrays. RNA <\/em>16:382-393. PMCID: PMC2811667<\/p>\n<h5 style=\"text-align: justify;\">TYPE III SECRETION<\/h5>\n<figure id=\"attachment_20792\" aria-describedby=\"caption-attachment-20792\" style=\"width: 375px\" class=\"wp-caption alignright\"><img loading=\"lazy\" src=\"\/ppb\/files\/2023\/05\/MxiH_IpaDplusminusTEV_most-365x300.jpg\" alt=\"\" width=\"365\" height=\"300\" class=\"wp-image-20792 size-medium\" srcset=\"https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/MxiH_IpaDplusminusTEV_most-365x300.jpg 365w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/MxiH_IpaDplusminusTEV_most-1024x843.jpg 1024w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/MxiH_IpaDplusminusTEV_most-768x632.jpg 768w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/MxiH_IpaDplusminusTEV_most-1536x1264.jpg 1536w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/MxiH_IpaDplusminusTEV_most-2048x1685.jpg 2048w\" sizes=\"(max-width: 365px) 100vw, 365px\" \/><figcaption id=\"caption-attachment-20792\" class=\"wp-caption-text\">Type III Secretion System Needle Tips: A) Nascent needle tip with wild type IpaD B) Immature needle tip with only needle proteins C) Nascent needle tip (mesh) with distal domain of IpaD cleaved (green) D) Superposition of nascent (mesh) and immature (magenta) needle tips<\/figcaption><\/figure>\n<p style=\"text-align: justify;\">Only 10 bacteria (or fewer!) are needed for Shigella flexneri to cause dysentery (bloody diarrhea). This disease is initiated via the type III secretion system, which is used to secrete both toxins and bacterial effectors that alter normal host cell functions to promote bacterial growth and spread.<\/p>\n<figure id=\"attachment_20791\" aria-describedby=\"caption-attachment-20791\" style=\"width: 414px\" class=\"wp-caption alignleft\"><img loading=\"lazy\" src=\"\/ppb\/files\/2023\/05\/IpaD_ribbon_confchange_and_segmented_EM_map-404x300.jpg\" alt=\"\" width=\"404\" height=\"300\" class=\"wp-image-20791 size-medium\" srcset=\"https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/IpaD_ribbon_confchange_and_segmented_EM_map-404x300.jpg 404w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/IpaD_ribbon_confchange_and_segmented_EM_map-1024x760.jpg 1024w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/IpaD_ribbon_confchange_and_segmented_EM_map-768x570.jpg 768w, https:\/\/www.bumc.bu.edu\/ppb\/files\/2023\/05\/IpaD_ribbon_confchange_and_segmented_EM_map.jpg 1247w\" sizes=\"(max-width: 404px) 100vw, 404px\" \/><figcaption id=\"caption-attachment-20791\" class=\"wp-caption-text\">Distal Domain of IpaD is flipped up in nascent needle tip: A segmented map of the nascent needle tip shows that a conformational change is needed to fit the crystal structure (pdb 2j0o) into the EM density map<\/figcaption><\/figure>\n<p style=\"text-align: justify;\">To understand (and disrupt) the process of infection, we are examining assembly intermediates of the T3SS syringe-like needle and its tip structure. Through our collaborations with the Picking lab at Oklahoma State University Stillwater and the Geisbrecht lab at the University of Missouri Kansas City we have shown that IpaD, the first protein that localizes to the needle tip, is present as a pentamer, and undergoes a dramatic conformational change as compared to the structure that has been solved by x-ray crystallography.<\/p>\n<p style=\"text-align: justify;\">The structures of three-dimensional reconstructions of immature and nascent needle tips show clearly IpaD as an elongated pentameric structure.<\/p>\n<p style=\"text-align: justify;\">This new result demonstrates that the distal domain of IpaD flips up, as compared to the structure solved by X-ray crystallography (pdb 2j0o).<\/p>\n<p style=\"text-align: justify;\">Diagram to the right shows the conformational change of the distal domain that is needed to fit the crystal structure of IpaD into our density map of 3-dimensional reconstructions from electron microscopy data.<\/p>\n<p style=\"text-align: justify;\"><span style=\"text-decoration: underline;\">Epler, C.R<\/span>., N.E. Dickenson, <strong>E. Bullitt<\/strong>*, W.L. Picking* <em>(2012). Ultrastructural analysis of IpaD at the tip of the nascent MxiH type III secretion apparatus of Shigella flexneri. J. Mol. Biol. 420:29-39. PMID: 22480614 *corresponding authors<\/em><\/p>\n<h5 class=\"Default\">Links:<\/h5>\n<p><a href=\"https:\/\/www.bumc.bu.edu\/busm\/profile\/esther-bullitt\/\">Faculty Profile<\/a><br \/>\n<a href=\"https:\/\/orcid.org\/0000-0003-2447-6209\">ORCID<\/a><br \/>\n<a href=\"https:\/\/www.ncbi.nlm.nih.gov\/myncbi\/1-_pjCESL6eUy6\/bibliography\/public\/\">MyNCBI<\/a><br \/>\n<strong><a href=\"https:\/\/www.ncbi.nlm.nih.gov\/pubmed\/?term=Bullitt%2C+Esther%5BFull+Author+Name%5D\" class=\"default\">PubMed Citations<\/a><\/strong><\/p>\n<p class=\"Default\"><b><span>Selected Media Coverage:<o:p><\/o:p><\/span><\/b><\/p>\n<p class=\"Default\"><span><a href=\"https:\/\/www.genengnews.com\/news\/diarrheal-disease-protection-may-literally-be-within-spitting-distance\/?utm_medium=newsletter&amp;utm_source=GEN%20Daily%20News%20Highlights&amp;utm_content=03&amp;utm_campaign=GEN%20Daily%20News%20Highlights_20180308&amp;oly_enc_id=0028E7638790I4U\">Diarrheal Disease Protection May Literally Be within Spitting Distance<\/a><o:p><\/o:p><\/span><\/p>\n<p>&nbsp;<\/p>\n<h5><strong><a name=\"contact\" id=\"contact\"><\/a>Contact Us<\/strong><\/h5>\n<p>Esther Bullitt, Ph.D.<br \/>\nDepartment of Pharmacology, Physiology &amp; Biophysics<br \/>\nChobanian &amp; Avedisian School of Medicine<br \/>\n700 Albany Street<br \/>\nBoston MA 02118-2526<\/p>\n<p>Phone: (617) 358-8464<br \/>\n<span>e-mail:<\/span> <a href=\"mailto:bullitt@bu.edu\">bullitt@bu.edu<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Working Together to\u00a0Promote an Inclusive Community I SUPPORT EQUITY AND INCLUSION, AND THE BLACK LIVES MATTER MOVEMENT Bullitt Lab Research Protein Structure Facilitates Function Using Electron Microscopy and Quantitative Image Analysis to see how Macromolecular Assemblies Work Structural studies of biological macromolecular assemblies are providing a deeper understanding of cellular function. In our laboratory, we [&hellip;]<\/p>\n","protected":false},"author":1811,"featured_media":0,"parent":0,"menu_order":41,"comment_status":"closed","ping_status":"closed","template":"page-templates\/no-sidebars.php","meta":[],"_links":{"self":[{"href":"https:\/\/www.bumc.bu.edu\/ppb\/wp-json\/wp\/v2\/pages\/21590"}],"collection":[{"href":"https:\/\/www.bumc.bu.edu\/ppb\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.bumc.bu.edu\/ppb\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.bumc.bu.edu\/ppb\/wp-json\/wp\/v2\/users\/1811"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bumc.bu.edu\/ppb\/wp-json\/wp\/v2\/comments?post=21590"}],"version-history":[{"count":2,"href":"https:\/\/www.bumc.bu.edu\/ppb\/wp-json\/wp\/v2\/pages\/21590\/revisions"}],"predecessor-version":[{"id":21592,"href":"https:\/\/www.bumc.bu.edu\/ppb\/wp-json\/wp\/v2\/pages\/21590\/revisions\/21592"}],"wp:attachment":[{"href":"https:\/\/www.bumc.bu.edu\/ppb\/wp-json\/wp\/v2\/media?parent=21590"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}