{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T12:00:08Z","timestamp":1790769608141,"version":"4.1.0"},"reference-count":63,"publisher":"Wiley","issue":"11","license":[{"start":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T00:00:00Z","timestamp":1790726400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"},{"start":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T00:00:00Z","timestamp":1790726400000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Protein Science"],"published-print":{"date-parts":[[2026,11]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    HIV\u20101 Vpu supports viral adaptation through host\u2010protein interactions. Although mainly membrane\u2010associated, we recently identified a soluble Vpu form that forms a stable complex with Ca\n                    <jats:sup>2+<\/jats:sup>\n                    \u2010bound calmodulin (Ca\n                    <jats:sup>2+<\/jats:sup>\n                    \u2013CaM), potentially influencing Vpu trafficking. Here, to determine the binding affinity and identify regions of soluble Vpu involved in CaM binding, we used ensemble F\u00f6rster resonance energy transfer (eFRET). We tested Cy3\u2010labeled full\u2010length (FL) Vpu, a C\u2010terminal fragment (helices 2 and 3), and a Cy3\u2010labeled FL Vpu V22A\/W23Y\/I33N mutant with substitutions of key residues in Vpu's helix 1 and helices 1\u2010to\u20102 loop having a role in the interaction with Ca\n                    <jats:sup>2+<\/jats:sup>\n                    \u2013CaM. All Vpu variants were labeled at residue L42C. Ca\n                    <jats:sup>2+<\/jats:sup>\n                    \u2013CaM was tagged with Cy5 at residue S39C. eFRET analysis of 100\u2009nM Cy3\u2010Vpu variants mixed with Cy5\u2013Ca\n                    <jats:sup>2+<\/jats:sup>\n                    \u2013CaM (in the range 100\u2009nM\u20132.5\u2009\u03bcM) revealed heterocomplexes formation with characteristic dissociation constants (\n                    <jats:italic>K<\/jats:italic>\n                    <jats:sub>\n                      <jats:italic>d<\/jats:italic>\n                    <\/jats:sub>\n                    ) and binding free energies (\n                    <jats:italic>\u2206G<\/jats:italic>\n                    ). FL Vpu\u2013Ca\n                    <jats:sup>2+<\/jats:sup>\n                    \u2013CaM showed highest stability (\n                    <jats:italic>K<\/jats:italic>\n                    <jats:sub>\n                      <jats:italic>d<\/jats:italic>\n                    <\/jats:sub>\n                    \u2009~74\u2009nM,\n                    <jats:italic>\u2206G<\/jats:italic>\n                    \u2009~\u22129.7\u2009kcal\/mol), while the truncated C\u2010terminal region and V22A\/W23Y\/I33N mutant formed weaker complexes with Ca\n                    <jats:sup>2+<\/jats:sup>\n                    \u2013CaM (\n                    <jats:italic>K<\/jats:italic>\n                    <jats:sub>\n                      <jats:italic>d<\/jats:italic>\n                    <\/jats:sub>\n                    ~182\u2009nM and 800\u2009nM,\n                    <jats:italic>\u2206G<\/jats:italic>\n                    \u2009~\u22129.2\u2009kcal\/mol and ~\u22128.3\u2009kcal\/mol). The reduced Vpu\u2013Ca\n                    <jats:sup>2+<\/jats:sup>\n                    \u2013CaM stability after disruption of binding sites in and near Vpu helix 1 may explain how this interaction is regulated, including through lipid competition that promotes Vpu membrane insertion. We propose that, at the membrane, hydrophobic helix 1 dissociates from Ca\n                    <jats:sup>2+<\/jats:sup>\n                    \u2013CaM and inserts into the lipid bilayer, weakening the complex and releasing CaM. These findings clarify HIV\u20101 Vpu interactions with cellular components and may inform antiviral development.\n                  <\/jats:p>","DOI":"10.1002\/pro.70811","type":"journal-article","created":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T11:21:21Z","timestamp":1790767281000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Quantitative and amino acid sequence analysis of soluble\n                    <scp>HIV<\/scp>\n                    \u20101 Vpu and calmodulin interactions"],"prefix":"10.1002","volume":"35","author":[{"given":"Adeyemi","family":"Ogunbowale","sequence":"first","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Tech University  Lubbock Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elaheh","family":"Hadadianpour","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Tech University  Lubbock Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Olamide","family":"Ishola","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Tech University  Lubbock Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Md Majharul","family":"Islam","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Tech University  Lubbock Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Natalie","family":"Ramos","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Tech University  Lubbock Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Arvin Saffarian","family":"Delkhosh","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Tech University  Lubbock Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9980-5260","authenticated-orcid":false,"given":"Elka R.","family":"Georgieva","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Tech University  Lubbock Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,9,30]]},"reference":[{"key":"e_1_2_9_2_1","doi-asserted-by":"publisher","DOI":"10.1242\/jcs.114082"},{"key":"e_1_2_9_3_1","doi-asserted-by":"publisher","DOI":"10.1038\/ni.3157"},{"key":"e_1_2_9_4_1","doi-asserted-by":"publisher","DOI":"10.1110\/ps.9.6.1137"},{"key":"e_1_2_9_5_1","doi-asserted-by":"publisher","DOI":"10.1038\/nrm.2017.7"},{"key":"e_1_2_9_6_1","doi-asserted-by":"publisher","DOI":"10.1021\/acs.jpcb.3c06222"},{"key":"e_1_2_9_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jbc.2025.111102"},{"key":"e_1_2_9_8_1","doi-asserted-by":"publisher","DOI":"10.3390\/molecules26051219"},{"issue":"41","key":"e_1_2_9_9_1","doi-asserted-by":"crossref","DOI":"10.1073\/pnas.2305100120","article-title":"A thermodynamic analysis of CLC transporter dimerization in lipid bilayers","volume":"120","author":"Chadda R","year":"2023","journal-title":"Proc Natl Acad Sci"},{"key":"e_1_2_9_10_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0056655"},{"key":"e_1_2_9_11_1","doi-asserted-by":"publisher","DOI":"10.1186\/s43556-025-00350-y"},{"key":"e_1_2_9_12_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41598-021-95"},{"issue":"6182","key":"e_1_2_9_13_1","doi-asserted-by":"crossref","first-page":"532","DOI":"10.1038\/334532a0","article-title":"Identification of a protein encoded by the vpu gene of HIV\u20101","volume":"334","author":"Cohen EA","year":"1988","journal-title":"Nature"},{"issue":"4","key":"e_1_2_9_14_1","doi-asserted-by":"crossref","first-page":"e01920","DOI":"10.1128\/mBio.01920-21","article-title":"HIV\u20101 Vpu promotes phagocytosis of infected CD4+ T cells by macrophages through downregulation of CD47","volume":"12","author":"Cong L","year":"2021","journal-title":"MBio"},{"key":"e_1_2_9_15_1","doi-asserted-by":"publisher","DOI":"10.1186\/s12964-016-0131-4"},{"key":"e_1_2_9_16_1","doi-asserted-by":"publisher","DOI":"10.1021\/bi301039t"},{"key":"e_1_2_9_17_1","doi-asserted-by":"publisher","DOI":"10.3390\/biom11091294"},{"key":"e_1_2_9_18_1","doi-asserted-by":"publisher","DOI":"10.1186\/1742-4690-7-114"},{"key":"e_1_2_9_19_1","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M110.179093"},{"key":"e_1_2_9_20_1","doi-asserted-by":"publisher","DOI":"10.3390\/v7082824"},{"key":"e_1_2_9_21_1","doi-asserted-by":"publisher","DOI":"10.1021\/ct400273t"},{"key":"e_1_2_9_22_1","doi-asserted-by":"publisher","DOI":"10.1007\/s11262-007-0125-9"},{"key":"e_1_2_9_23_1","doi-asserted-by":"publisher","DOI":"10.1110\/ps.23702"},{"key":"e_1_2_9_24_1","doi-asserted-by":"publisher","DOI":"10.1038\/nri2302"},{"key":"e_1_2_9_25_1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.94.8.3668"},{"key":"e_1_2_9_26_1","doi-asserted-by":"publisher","DOI":"10.1186\/1743-422X-4-81"},{"key":"e_1_2_9_27_1","doi-asserted-by":"publisher","DOI":"10.1002\/pro.70487Digital"},{"key":"e_1_2_9_28_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41598-018-35"},{"key":"e_1_2_9_29_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41586-021-03819-2"},{"key":"e_1_2_9_30_1","doi-asserted-by":"publisher","DOI":"10.3390\/v13081466"},{"key":"e_1_2_9_31_1","doi-asserted-by":"publisher","DOI":"10.1006\/jmbi.2001.4822"},{"key":"e_1_2_9_32_1","doi-asserted-by":"publisher","DOI":"10.7554\/eLife.41930"},{"key":"e_1_2_9_33_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jsb.2023.107943"},{"key":"e_1_2_9_34_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41598-023-41"},{"key":"e_1_2_9_35_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.ppat.1003299"},{"key":"e_1_2_9_36_1","doi-asserted-by":"publisher","DOI":"10.1002\/prot.23048"},{"key":"e_1_2_9_37_1","doi-asserted-by":"publisher","DOI":"10.1089\/aid.1993.9.1057"},{"key":"e_1_2_9_38_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.celrep.2022.111251"},{"issue":"7177","key":"e_1_2_9_39_1","doi-asserted-by":"crossref","first-page":"425","DOI":"10.1038\/nature06553","article-title":"Tetherin inhibits retrovirus release and is antagonized by HIV\u20101 Vpu","volume":"451","author":"Neil SJ","year":"2008","journal-title":"Nature"},{"key":"e_1_2_9_40_1","doi-asserted-by":"publisher","DOI":"10.1186\/s12868-022-00695-y"},{"key":"e_1_2_9_41_1","doi-asserted-by":"publisher","DOI":"10.1016\/0968-0004(90)90177-d"},{"key":"e_1_2_9_42_1","doi-asserted-by":"publisher","DOI":"10.1063\/1.4915279"},{"key":"e_1_2_9_43_1","doi-asserted-by":"publisher","DOI":"10.1038\/12271"},{"key":"e_1_2_9_44_1","doi-asserted-by":"publisher","DOI":"10.1016\/s0162-3109(98)00018-6"},{"key":"e_1_2_9_45_1","doi-asserted-by":"publisher","DOI":"10.1529\/biophysj.106.087106"},{"key":"e_1_2_9_46_1","doi-asserted-by":"publisher","DOI":"10.1006\/bbrc.1996.0034"},{"key":"e_1_2_9_47_1","doi-asserted-by":"publisher","DOI":"10.1089\/088922200750006047"},{"key":"e_1_2_9_48_1","doi-asserted-by":"publisher","DOI":"10.3389\/fmicb.2020.559792"},{"key":"e_1_2_9_49_1","doi-asserted-by":"publisher","DOI":"10.1096\/fasebj.11.5.9141499"},{"key":"e_1_2_9_50_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.tibs.2022.09.008"},{"key":"e_1_2_9_51_1","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M111.273623"},{"key":"e_1_2_9_52_1","doi-asserted-by":"publisher","DOI":"10.1089\/aid.2007.0202"},{"key":"e_1_2_9_53_1","doi-asserted-by":"publisher","DOI":"10.1021\/bi051766k"},{"key":"e_1_2_9_54_1","doi-asserted-by":"publisher","DOI":"10.3390\/ijms16046718"},{"key":"e_1_2_9_55_1","doi-asserted-by":"publisher","DOI":"10.1126\/science.3261888"},{"key":"e_1_2_9_56_1","doi-asserted-by":"publisher","DOI":"10.1111\/febs.12296"},{"issue":"4","key":"e_1_2_9_57_1","doi-asserted-by":"crossref","first-page":"245","DOI":"10.1016\/j.chom.2008.03.001","article-title":"The interferon\u2010induced protein BST\u20102 restricts HIV\u20101 release and is downregulated from the cell surface by the viral Vpu protein","volume":"3","author":"Damme N","year":"2008","journal-title":"Cell Host Microbe"},{"key":"e_1_2_9_58_1","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M113.543694"},{"key":"e_1_2_9_59_1","doi-asserted-by":"publisher","DOI":"10.3390\/biom14091061"},{"key":"e_1_2_9_60_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.chom.2021.07.003"},{"issue":"16","key":"e_1_2_9_61_1","doi-asserted-by":"crossref","first-page":"8047","DOI":"10.1128\/JVI.00252-06","article-title":"Contribution of Vpu, env, and Nef to CD4 down\u2010modulation and resistance of human immunodeficiency virus type 1\u2010infected T cells to superinfection","volume":"80","author":"Wildum S","year":"2006","journal-title":"J Virol"},{"issue":"12","key":"e_1_2_9_62_1","doi-asserted-by":"crossref","first-page":"7193","DOI":"10.1128\/jvi.66.12.7193-7200.1992","article-title":"Human immunodeficiency virus type 1 Vpu protein induces rapid degradation of CD4","volume":"66","author":"Willey R","year":"1992","journal-title":"J Virol"},{"issue":"19","key":"e_1_2_9_63_1","doi-asserted-by":"crossref","DOI":"10.1002\/advs.202414777","article-title":"Direct quantification of protein\u2013protein interactions in living bacterial cells","volume":"12","author":"Yi S","year":"2025","journal-title":"Adv Sci"},{"key":"e_1_2_9_64_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.bbamem.2015.09.008"}],"container-title":["Protein Science"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/pro.70811","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/full-xml\/10.1002\/pro.70811","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/pro.70811","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T11:21:23Z","timestamp":1790767283000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/pro.70811"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,30]]},"references-count":63,"journal-issue":{"issue":"11","published-print":{"date-parts":[[2026,11]]}},"alternative-id":["10.1002\/pro.70811"],"URL":"https:\/\/doi.org\/10.1002\/pro.70811","archive":["Portico"],"relation":{},"ISSN":["0961-8368","1469-896X"],"issn-type":[{"value":"0961-8368","type":"print"},{"value":"1469-896X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,30]]},"assertion":[{"value":"2026-04-22","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-09-17","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-09-30","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e70811"}}