{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,12]],"date-time":"2026-08-12T11:29:47Z","timestamp":1786534187122,"version":"build-2736575974"},"reference-count":47,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,8,12]],"date-time":"2026-08-12T00:00:00Z","timestamp":1786492800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"},{"start":{"date-parts":[[2026,8,12]],"date-time":"2026-08-12T00:00:00Z","timestamp":1786492800000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"funder":[{"DOI":"10.13039\/100000069","name":"National Institute of Arthritis and Musculoskeletal and Skin Diseases","doi-asserted-by":"publisher","award":["R01\u2010AR\u201057063"],"award-info":[{"award-number":["R01\u2010AR\u201057063"]}],"id":[{"id":"10.13039\/100000069","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Cytoskeleton"],"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:p>\n                    Mammals have four tropomyosin (TPM) genes (\n                    <jats:italic>TPM1, TPM2<\/jats:italic>\n                    ,\n                    <jats:italic>TPM3<\/jats:italic>\n                    , and\n                    <jats:italic>TPM4<\/jats:italic>\n                    ) that produce various isoforms through alternative splicing.\n                    <jats:italic>TPM1<\/jats:italic>\n                    generates both myofibrillar (Tpm1.1, Tpm1.2) and non\u2010myofibrillar isoforms, including those with an exon 9d peptide or with an exon 9a peptide. These non\u2010myofibrillar isoforms are involved in regulating actin\u2010based structures and processes in non\u2010muscle cells. This study focused on the expression of the non\u2010myofibrillar HMW Tpm1 isoforms (Tpm1.3, Tpm1.4, Tpm1.5, Tpm1.6, Tpm1.7, and Tpm1.14) during human inducible pluripotent stem cells (hiPSC) differentiation into cardiomyocytes (CMs) at different time points (Days 0, 5, 10, 15, 20). We have determined the expression of various Tpm1 transcripts by qRT\u2010PCR using isoform\u2010specific primer\u2010pairs. Western blotting with Tpm1\u2010exon 6a and Tpm1\u2010exon 9d antibodies and 2D Western blotting with Tpm1\u2010exon 6a antibody followed by mass spectra analyses were used to evaluate protein expression. Transcripts of non\u2010myofibrillar Tpm1 isoforms peaked at Day 15 and continued at a slightly lower level in mature hiPSC\u2010CM until Day 20. However, no expression of Tpm1.3 or Tpm1.14 has been observed. Protein expression of Tpm1.4, Tpm1.5, Tpm1.6, and Tpm1.7 increases up to Day 15 but practically disappears by Day 20 hiPSC\u2010CM, suggesting their production is decreased, or more likely they are degraded intracellularly. The results suggest that the proteins have the potential to be transiently involved in the early stages of CM differentiation. This study also demonstrates that Tpm1.5, when fused with YFP in an expression construct and transfected into embryonic chicken CM and Day 20 mature hiPSC\u2010CMs, can be organized into cardiac myofibrils despite being previously characterized as a non\u2010muscle isoform. Our observation is further substantiated by the fact that YFP\u2010Tpm1.5 fusion protein can be ectopically expressed and incorporated into the myofibrils of chicken myotube skeletal muscle, which is known to be more stringent than cardiac muscle with regards to myofibril remodeling. Paradoxically, anti\u20106a antibody fails to recognize the organized YFP\u2010Tpm1.5 fusion protein in embryonic chicken CMs, embryonic chicken skeletal muscle myotubes, or in Day 20 mature hiPSC\u2010CMs. Interestingly, the antibody recognizes the denatured YFP\u2010Tpm1 fusion protein in Western blot analyses. It is well\u2010documented in the literature that an antibody epitope may fail to recognize its antigen when the antigen is in its native state in living cells, often because the epitope is buried, altered conformationally, or inaccessible. Conversely, while the Tpm1.Ex6a antibody stains Tpm1.5 in cell nuclei, the YFP\u2010Tpm1.5 fusion protein does not localize to the cell nuclei. This suggests conformational differences between nuclear and cytoplasmic Tpm1 protein(s) and differential access of the fusion protein to different cellular locations. This also suggests that it is endogenous Tpm1 6a\u2010containing protein identified in the nuclei.\n                  <\/jats:p>","DOI":"10.1002\/cm.70185","type":"journal-article","created":{"date-parts":[[2026,8,12]],"date-time":"2026-08-12T10:36:10Z","timestamp":1786530970000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Transcripts and Protein Expression of Different\n                    <scp>HMW<\/scp>\n                    Non\u2010Myofibrillar Tpm1 Isoforms in Human\n                    <scp>iPSC<\/scp>\n                    \u2010\n                    <scp>CMs<\/scp>\n                    During Differentiation"],"prefix":"10.1002","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0205-4761","authenticated-orcid":false,"given":"Dipak K.","family":"Dube","sequence":"first","affiliation":[{"name":"Department of Medicine SUNY Upstate Medical University  Syracuse New York USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Syamalima","family":"Dube","sequence":"additional","affiliation":[{"name":"Department of Medicine SUNY Upstate Medical University  Syracuse New York USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Patricia","family":"Benz","sequence":"additional","affiliation":[{"name":"Department of Medicine SUNY Upstate Medical University  Syracuse New York USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-9800-074X","authenticated-orcid":false,"given":"Jushuo","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Cell and Developmental Biology SUNY Upstate Medical University  Syracuse New York USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5382-8245","authenticated-orcid":false,"given":"Samender","family":"Randhawa","sequence":"additional","affiliation":[{"name":"University of Pittsburgh Medical Center  Pittsburgh Pennsylvania USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0000-6216-9475","authenticated-orcid":false,"given":"Yingli","family":"Fan","sequence":"additional","affiliation":[{"name":"Department of Cell and Developmental Biology SUNY Upstate Medical University  Syracuse New York USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5228-105X","authenticated-orcid":false,"given":"Zhen","family":"Ma","sequence":"additional","affiliation":[{"name":"Department of Biomedical &amp; Chemical Engineering Syracuse University  Syracuse New York USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xinrui","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Pharmacology SUNY Upstate Medical University  Syracuse New York USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shiyang","family":"Sun","sequence":"additional","affiliation":[{"name":"Department of Biomedical &amp; Chemical Engineering Syracuse University  Syracuse New York USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2281-8490","authenticated-orcid":false,"given":"Joseph W.","family":"Sanger","sequence":"additional","affiliation":[{"name":"Department of Cell and Developmental Biology SUNY Upstate Medical University  Syracuse New York USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-7835-1467","authenticated-orcid":false,"given":"Jean M.","family":"Sanger","sequence":"additional","affiliation":[{"name":"Department of Cell and Developmental Biology SUNY Upstate Medical University  Syracuse New York USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1269-4658","authenticated-orcid":false,"given":"Bernard J.","family":"Poiesz","sequence":"additional","affiliation":[{"name":"Department of Medicine SUNY Upstate Medical University  Syracuse New York USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,8,12]]},"reference":[{"key":"e_1_2_9_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.diff.2011.10.002"},{"key":"e_1_2_9_3_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.stem.2011.12.013"},{"key":"e_1_2_9_4_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jbc.2021.101154"},{"key":"e_1_2_9_5_1","doi-asserted-by":"publisher","DOI":"10.1007\/s10974\u2010013\u20109356\u20107"},{"key":"e_1_2_9_6_1","doi-asserted-by":"publisher","DOI":"10.1016\/s0091\u2010679x(08)61959\u20107"},{"key":"e_1_2_9_7_1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.94.17.9493"},{"key":"e_1_2_9_8_1","doi-asserted-by":"publisher","DOI":"10.1002\/pmic.201000819"},{"key":"e_1_2_9_9_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.bbrc.2004.06.084"},{"key":"e_1_2_9_10_1","doi-asserted-by":"publisher","DOI":"10.1016\/0045\u20106039(88)90035\u20108"},{"key":"e_1_2_9_11_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ydbio.2008.03.011"},{"key":"e_1_2_9_12_1","doi-asserted-by":"publisher","DOI":"10.1155\/2023\/1303500"},{"key":"e_1_2_9_13_1","doi-asserted-by":"publisher","DOI":"10.1002\/cm.21495"},{"key":"e_1_2_9_14_1","doi-asserted-by":"publisher","DOI":"10.1002\/cm.21850"},{"key":"e_1_2_9_15_1","doi-asserted-by":"publisher","DOI":"10.4172\/2157\u20107099"},{"key":"e_1_2_9_16_1","doi-asserted-by":"publisher","DOI":"10.1155\/2015\/859427"},{"key":"e_1_2_9_17_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0121673"},{"key":"e_1_2_9_18_1","doi-asserted-by":"publisher","DOI":"10.1007\/s10974\u2010014\u20109389\u20106"},{"key":"e_1_2_9_19_1","doi-asserted-by":"crossref","first-page":"797","DOI":"10.1242\/jcs.112.6.797","article-title":"Conformational Difference Between Nuclear and Cytoplasmic Actin as Detected by a Monoclonal Antibody","volume":"112","author":"Gonsior S. 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