{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T05:30:08Z","timestamp":1791437408738,"version":"4.3.3"},"reference-count":34,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2020,10,18]],"date-time":"2020-10-18T00:00:00Z","timestamp":1602979200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cells"],"abstract":"<jats:p>Macroautophagy is a conserved degradative process for maintaining cellular homeostasis and plays a key role in aging and various human disorders. The microtubule-associated protein 1A\/1B light chain 3B (MAP1LC3B or LC3B) is commonly analyzed as a key marker for autophagosomes and as a proxy for autophagic flux. Three paralogues of the LC3 gene exist in humans: LC3A, LC3B and LC3C. The molecular function, regulation and cellular localization of LC3A and LC3C have not been investigated frequently, even if a similar function to that described for LC3B appears likely. Here, we have selectively decapacitated LC3B by three separate strategies in primary human fibroblasts and analyzed the evoked effects on LC3A, LC3B and LC3C in terms of their cellular distribution and co-localization with p62, a ubiquitin and autophagy receptor. First, treatment with pharmacological sirtuin 1 (SIRT1) inhibitors to prevent the translocation of LC3B from the nucleus into the cytosol induced an increase in cytosolic LC3C, a heightened co-localization of LC3C with p62, and an increase LC3C-dependent autophagic flux as assessed by protein lipidation. Cytosolic LC3A, however, was moderately reduced, but also more co-localized with p62. Second, siRNA-based knock-down of SIRT1 broadly reproduced these findings and increased the co-localization of LC3A and particularly LC3C with p62 in presumed autophagosomes. These effects resembled the effects of pharmacological sirtuin inhibition under normal and starvation conditions. Third, siRNA-based knock-down of total LC3B in cytosol and nucleus also induced a redistribution of LC3C as if to replace LC3B in the nucleus, but only moderately affected LC3A. Total protein expression of LC3A, LC3B, LC3C, GABARAP and GABARAP-L1 following LC3B decapacitation was unaltered. Our data indicate that nuclear trapping and other causes of LC3B functional loss in the cytosol are buffered by LC3A and actively compensated by LC3C, but not by GABARAPs. The biological relevance of the potential functional compensation of LC3B decapacitation by LC3C and LC3A warrants further study.<\/jats:p>","DOI":"10.3390\/cells9102315","type":"journal-article","created":{"date-parts":[[2020,10,18]],"date-time":"2020-10-18T21:26:06Z","timestamp":1603056366000},"page":"2315","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":62,"title":["Novel Insights into the Cellular Localization and Regulation of the Autophagosomal Proteins LC3A, LC3B and LC3C"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7223-8048","authenticated-orcid":false,"given":"Marius W.","family":"Baeken","sequence":"first","affiliation":[{"name":"Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katja","family":"Weckmann","sequence":"additional","affiliation":[{"name":"Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Philip","family":"Diefenth\u00e4ler","sequence":"additional","affiliation":[{"name":"Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jan","family":"Schulte","sequence":"additional","affiliation":[{"name":"Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kamran","family":"Yusifli","sequence":"additional","affiliation":[{"name":"Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bernd","family":"Moosmann","sequence":"additional","affiliation":[{"name":"Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christian","family":"Behl","sequence":"additional","affiliation":[{"name":"Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Parvana","family":"Hajieva","sequence":"additional","affiliation":[{"name":"Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany"},{"name":"Institute for Molecular Medicine, MSH Medical School, 20457 Hamburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,10,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"158","DOI":"10.1007\/BF01923509","article-title":"Autophagy and other vacuolar protein degradation mechanisms","volume":"48","author":"Seglen","year":"1992","journal-title":"Experientia"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"728","DOI":"10.1016\/j.cell.2011.10.026","article-title":"Autophagy: Renovation of cells and tissues","volume":"147","author":"Mizushima","year":"2011","journal-title":"Cell"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2337","DOI":"10.1038\/s41598-018-19421-y","article-title":"Metabolomics profiling reveals differential adaptation of major energy metabolism pathways associated with autophagy upon oxygen and glucose reduction","volume":"8","author":"Weckmann","year":"2018","journal-title":"Sci. Rep."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1845","DOI":"10.1056\/NEJMra1205406","article-title":"Autophagy in human health and disease","volume":"368","author":"Choi","year":"2013","journal-title":"N. Eng. J. Med."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"90","DOI":"10.3389\/fendo.2018.00790","article-title":"Hallmarks of aging: An autophagic perspective","volume":"9","author":"Barbosa","year":"2019","journal-title":"Front. Endocrinol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1080\/15548627.2015.1100356","article-title":"Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)","volume":"12","author":"Klionsky","year":"2016","journal-title":"Autophagy"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"29278","DOI":"10.1074\/jbc.M303800200","article-title":"Post-translational Modifications of Three Members of the Human MAP1LC3 Family and Detection of a Novel Type of Modification for MAP1LC3B","volume":"278","author":"He","year":"2003","journal-title":"J. Biol. Chem."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1038\/embor.2012.220","article-title":"Non-autophagic roles of autophagy-related proteins","volume":"14","author":"Subramani","year":"2013","journal-title":"EMBO Rep."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"3961","DOI":"10.1096\/fj.201600698R","article-title":"LC3\/GABARAP family proteins: Autophagy-(un)related functions","volume":"30","author":"Schaaf","year":"2016","journal-title":"FASEB J."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"456","DOI":"10.1016\/j.molcel.2014.12.013","article-title":"Deacetylation of Nuclear LC3 Drives Autophagy Initiation under Starvation","volume":"57","author":"Huang","year":"2015","journal-title":"Mol. Cell"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"857","DOI":"10.1083\/jcb.201607039","article-title":"Atg8 family LC3\/GABARAP proteins are crucial for autophagosome-lysosome fusion but not autophagosome formation during PINK1\/Parkin mitophagy and starvation","volume":"215","author":"Nguyen","year":"2016","journal-title":"J. Cell Biol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1036","DOI":"10.1126\/science.aaf6136","article-title":"The ATG conjugation systems are important for degradation of the inner autophagosomal membrane","volume":"354","author":"Tsuboyama","year":"2016","journal-title":"Science"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"879","DOI":"10.3233\/JAD-140600","article-title":"The Cleavage Product of Amyloid-\u03b2 Protein Precursor sA\u03b2PP\u03b1 Modulates BAG3-Dependent Aggresome Formation and Enhances Cellular Proteasomal Activity","volume":"44","author":"Renziehausen","year":"2015","journal-title":"J. Alzheimer\u2019s Dis."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"D754","DOI":"10.1093\/nar\/gkx1098","article-title":"Ensembl 2018","volume":"46","author":"Zerbino","year":"2018","journal-title":"Nucleic Acids Res."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"W242","DOI":"10.1093\/nar\/gkw290","article-title":"Interactive tree of life (iTOL) v3: An online tool for the display and annotation of phylogenetic and other trees","volume":"44","author":"Letunic","year":"2016","journal-title":"Nucleic Acids Res."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"462","DOI":"10.1016\/j.molcel.2011.08.035","article-title":"Structural Basis of Atg8 Activation by a Homodimeric E1, Atg7","volume":"44","author":"Noda","year":"2011","journal-title":"Mol. Cell"},{"key":"ref_17","first-page":"488","article-title":"A ubiquitin-like system mediates protein lipidation","volume":"408","author":"Ichimura","year":"2000","journal-title":"Nat. Cell Biol."},{"key":"ref_18","first-page":"3","article-title":"The LC3 interactome at a glance","volume":"127","author":"Wild","year":"2014","journal-title":"J. Cell Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"3237","DOI":"10.1242\/jcs.126128","article-title":"The LIR motif\u2014Crucial for selective autophagy","volume":"126","author":"Birgisdottir","year":"2013","journal-title":"J. Cell Sci."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"549","DOI":"10.15252\/embj.201695063","article-title":"Fluorescence-based ATG8 sensors monitor localization and function of LC3\/GABARAP proteins","volume":"36","author":"Stolz","year":"2017","journal-title":"EMBO J."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"970","DOI":"10.1016\/j.bbrc.2013.11.007","article-title":"LC3B-II deacetylation by histone deacetylase 6 is involved in serum-starvation-induced autophagic degradation","volume":"441","author":"Liu","year":"2013","journal-title":"Biochem. Biophys. Res. Commun."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"8045","DOI":"10.1021\/jm050522v","article-title":"Discovery of Indoles as Potent and Selective Inhibitors of the Deacetylase SIRT1","volume":"48","author":"Napper","year":"2005","journal-title":"J. Med. Chem."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"372","DOI":"10.1006\/bbrc.1999.0316","article-title":"Neuronal differentiation of neuro 2a cells by inhibitors of cell cycle progression, trichostatin A and butyrolactone I","volume":"256","author":"Inokoshi","year":"1999","journal-title":"Biochem. Biophys. Res. Commun."},{"key":"ref_24","first-page":"105","article-title":"Autophagy mediates degradation of nuclear lamina","volume":"527","author":"Dou","year":"2015","journal-title":"Nat. Cell Biol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"204","DOI":"10.1016\/j.tplants.2016.11.015","article-title":"ATG8 expansion: A driver of selective autophagy diversification?","volume":"22","author":"Kellner","year":"2017","journal-title":"Trends Plant Sci."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Koukourakis, M.I., Kalamida, D., Giatromanolaki, A., Zois, C.E., Sivridis, E., Pouliliou, S., Mitrakas, A., Gatter, K.C., and Harris, A.L. (2015). Autophagosome Proteins LC3A, LC3B and LC3C Have Distinct Subcellular Distribution Kinetics and Expression in Cancer Cell Lines. PLoS ONE, 10.","DOI":"10.1371\/journal.pone.0137675"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1016\/j.molcel.2015.09.010","article-title":"TECPR2 Cooperates with LC3C to Regulate COPII-Dependent ER Export","volume":"60","author":"Stadel","year":"2015","journal-title":"Mol. Cell"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"329","DOI":"10.1016\/j.molcel.2012.08.024","article-title":"LC3C, Bound Selectively by a Noncanonical LIR Motif in NDP52, Is Required for Antibacterial Autophagy","volume":"48","author":"Akutsu","year":"2012","journal-title":"Mol. Cell"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"786","DOI":"10.1016\/j.molcel.2017.10.029","article-title":"Autophagosomal Content Profiling Reveals an LC3C-Dependent Piecemeal Mitophagy Pathway","volume":"68","author":"Eck","year":"2017","journal-title":"Mol. Cell"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"20180025","DOI":"10.1098\/rsfs.2018.0025","article-title":"Human ubiquitin-like proteins as central coordinators in autophagy","volume":"8","author":"Mohan","year":"2018","journal-title":"Interface Focus"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"947","DOI":"10.15252\/embr.201643147","article-title":"FKBP8 recruits LC3A to mediate Parkin-independent mitophagy","volume":"18","author":"Bhujabal","year":"2017","journal-title":"EMBO Rep."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1016\/j.yexcr.2015.02.003","article-title":"Autophagic bulk sequestration of cytosolic cargo is independent of LC3, but requires GABARAPs","volume":"333","author":"Szalai","year":"2015","journal-title":"Exp. Cell Res."},{"key":"ref_33","first-page":"e00392-17","article-title":"Systematic analysis of human cells lacking ATG8 proteins uncovers roles for GABARAPs and the CCZ1\/MON1 regulator C18orf8\/RMC1 in macro and selective autophagic flux","volume":"38","author":"Paulo","year":"2017","journal-title":"Mol. Cell Biol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"64","DOI":"10.1016\/j.arr.2018.02.004","article-title":"Role of Sirtuin1-p53 regulatory axis in aging, cancer and cellular reprogramming","volume":"43","author":"Ong","year":"2018","journal-title":"Ageing Res. Rev."}],"container-title":["Cells"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4409\/9\/10\/2315\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T10:23:29Z","timestamp":1760178209000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4409\/9\/10\/2315"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,10,18]]},"references-count":34,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2020,10]]}},"alternative-id":["cells9102315"],"URL":"https:\/\/doi.org\/10.3390\/cells9102315","relation":{},"ISSN":["2073-4409"],"issn-type":[{"value":"2073-4409","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,10,18]]}}}