Par complex cluster formation mediated by phase separation.


Journal

Nature communications
ISSN: 2041-1723
Titre abrégé: Nat Commun
Pays: England
ID NLM: 101528555

Informations de publication

Date de publication:
08 05 2020
Historique:
received: 28 07 2019
accepted: 16 04 2020
entrez: 10 5 2020
pubmed: 10 5 2020
medline: 6 8 2020
Statut: epublish

Résumé

The evolutionarily conserved Par3/Par6/aPKC complex regulates the polarity establishment of diverse cell types and distinct polarity-driven functions. However, how the Par complex is concentrated beneath the membrane to initiate cell polarization remains unclear. Here we show that the Par complex exhibits cell cycle-dependent condensation in Drosophila neuroblasts, driven by liquid-liquid phase separation. The open conformation of Par3 undergoes autonomous phase separation likely due to its NTD-mediated oligomerization. Par6, via C-terminal tail binding to Par3 PDZ3, can be enriched to Par3 condensates and in return dramatically promote Par3 phase separation. aPKC can also be concentrated to the Par3N/Par6 condensates as a client. Interestingly, activated aPKC can disperse the Par3/Par6 condensates via phosphorylation of Par3. Perturbations of Par3/Par6 phase separation impair the establishment of apical-basal polarity during neuroblast asymmetric divisions and lead to defective lineage development. We propose that phase separation may be a common mechanism for localized cortical condensation of cell polarity complexes.

Identifiants

pubmed: 32385244
doi: 10.1038/s41467-020-16135-6
pii: 10.1038/s41467-020-16135-6
pmc: PMC7211019
doi:

Substances chimiques

Drosophila Proteins 0
Multiprotein Complexes 0
Green Fluorescent Proteins 147336-22-9
Protein Kinase C EC 2.7.11.13

Types de publication

Journal Article Research Support, Non-U.S. Gov't

Langues

eng

Sous-ensembles de citation

IM

Pagination

2266

Références

Nelson, W. J. Adaptation of core mechanisms to generate cell polarity. Nature 422, 766–774 (2003).
pubmed: 12700771 pmcid: 3373010 doi: 10.1038/nature01602
St Johnston, D. & Ahringer, J. Cell polarity in eggs and epithelia: parallels and diversity. Cell 141, 757–774 (2010).
doi: 10.1016/j.cell.2010.05.011
Rodriguez-Boulan, E. & Macara, I. G. Organization and execution of the epithelial polarity programme. Nat. Rev. Mol. Cell Biol. 15, 225–242 (2014).
pubmed: 24651541 pmcid: 4211427 doi: 10.1038/nrm3775
Wen, W. & Zhang, M. Protein complex assemblies in epithelial cell polarity and asymmetric cell division. J. Mol. Biol. 430, 3504–3520 (2018).
pubmed: 28963071 doi: 10.1016/j.jmb.2017.09.013
Kemphues, K. PARsing embryonic polarity. Cell 101, 345–348 (2000).
pubmed: 10830161 doi: 10.1016/S0092-8674(00)80844-2
Hoege, C. & Hyman, A. A. Principles of PAR polarity in Caenorhabditis elegans embryos. Nat. Rev. Mol. Cell Biol. 14, 315–322 (2013).
pubmed: 23594951 doi: 10.1038/nrm3558
Gonczy, P. Mechanisms of asymmetric cell division: flies and worms pave the way. Nat. Rev. Mol. Cell Biol. 9, 355–366 (2008).
pubmed: 18431399 doi: 10.1038/nrm2388 pmcid: 18431399
Knoblich, J. A. Asymmetric cell division: recent developments and their implications for tumour biology. Nat. Rev. Mol. Cell Biol. 11, 849–860 (2010).
pubmed: 21102610 pmcid: 3941022 doi: 10.1038/nrm3010
Siller, K. H. & Doe, C. Q. Spindle orientation during asymmetric cell division. Nat. Cell Biol. 11, 365–374 (2009).
pubmed: 19337318 doi: 10.1038/ncb0409-365 pmcid: 19337318
Nishimura, T. & Kaibuchi, K. Numb controls integrin endocytosis for directional cell migration with aPKC and PAR-3. Dev. Cell 13, 15–28 (2007).
pubmed: 17609107 doi: 10.1016/j.devcel.2007.05.003 pmcid: 17609107
Arimura, N. & Kaibuchi, K. Neuronal polarity: from extracellular signals to intracellular mechanisms. Nat. Rev. Neurosci. 8, 194–205 (2007).
pubmed: 17311006 doi: 10.1038/nrn2056 pmcid: 17311006
Martin-Belmonte, F. & Perez-Moreno, M. Epithelial cell polarity, stem cells and cancer. Nat. Rev. Cancer 12, 23–38 (2011).
pubmed: 22169974 doi: 10.1038/nrc3169 pmcid: 22169974
Tepass, U. The apical polarity protein network in drosophila epithelial cells: regulation of polarity, junctions, morphogenesis, cell growth, and survival. Annu. Rev. Cell Dev. Biol. 28, 655–685 (2012).
pubmed: 22881460 doi: 10.1146/annurev-cellbio-092910-154033 pmcid: 22881460
Kennedy, M. B. Origin of PDZ (DHR, GLGF) domains. Trends Biochem. Sci. 20, 350 (1995).
pubmed: 7482701 doi: 10.1016/S0968-0004(00)89074-X pmcid: 7482701
Joberty, G., Petersen, C., Gao, L. & Macara, I. G. The cell-polarity protein Par6 links Par3 and atypical protein kinase C to Cdc42. Nat. Cell Biol. 2, 531–539 (2000).
pubmed: 10934474 doi: 10.1038/35019573 pmcid: 10934474
Lin, D. et al. A mammalian PAR-3-PAR-6 complex implicated in Cdc42/Rac1 and aPKC signalling and cell polarity. Nat. Cell Biol. 2, 540–547 (2000).
pubmed: 10934475 doi: 10.1038/35019582 pmcid: 10934475
Renschler, F. A. et al. Structural basis for the interaction between the cell polarity proteins Par3 and Par6. Sci. Signal. 11, eaam9899 (2018).
pubmed: 29440511 doi: 10.1126/scisignal.aam9899 pmcid: 29440511
Wilson, M. I., Gill, D. J., Perisic, O., Quinn, M. T. & Williams, R. L. PB1 domain-mediated heterodimerization in NADPH oxidase and signaling complexes of atypical protein kinase C with Par6 and p62. Mol. Cell 12, 39–50 (2003).
pubmed: 12887891 doi: 10.1016/S1097-2765(03)00246-6 pmcid: 12887891
Soriano, E. V. et al. aPKC inhibition by Par3 CR3 flanking regions controls substrate access and underpins apical-junctional polarization. Dev. Cell 38, 384–398 (2016).
pubmed: 27554858 pmcid: 4998004 doi: 10.1016/j.devcel.2016.07.018
Wirtz-Peitz, F., Nishimura, T. & Knoblich, J. A. Linking cell cycle to asymmetric division: Aurora-A phosphorylates the Par complex to regulate Numb localization. Cell 135, 161–173 (2008).
pubmed: 18854163 pmcid: 2989779 doi: 10.1016/j.cell.2008.07.049
Knoblich, J. A., Jan, L. Y. & Jan, Y. N. Asymmetric segregation of Numb and Prospero during cell division. Nature 377, 624–627 (1995).
pubmed: 7566172 doi: 10.1038/377624a0 pmcid: 7566172
Lu, B., Rothenberg, M., Jan, L. Y. & Jan, Y. N. Partner of Numb colocalizes with Numb during mitosis and directs Numb asymmetric localization in Drosophila neural and muscle progenitors. Cell 95, 225–235 (1998).
pubmed: 9790529 doi: 10.1016/S0092-8674(00)81753-5 pmcid: 9790529
Ikeshima-Kataoka, H., Skeath, J. B., Nabeshima, Y., Doe, C. Q. & Matsuzaki, F. Miranda directs Prospero to a daughter cell during Drosophila asymmetric divisions. Nature 390, 625–629 (1997).
pubmed: 9403694 doi: 10.1038/37641 pmcid: 9403694
Shen, C. P., Jan, L. Y. & Jan, Y. N. Miranda is required for the asymmetric localization of Prospero during mitosis in Drosophila. Cell 90, 449–458 (1997).
pubmed: 9267025 doi: 10.1016/S0092-8674(00)80505-X pmcid: 9267025
Petronczki, M. & Knoblich, J. A. DmPAR-6 directs epithelial polarity and asymmetric cell division of neuroblasts in Drosophila. Nat. Cell Biol. 3, 43–49 (2001).
pubmed: 11146625 doi: 10.1038/35050550 pmcid: 11146625
Schober, M., Schaefer, M. & Knoblich, J. A. Bazooka recruits Inscuteable to orient asymmetric cell divisions in Drosophila neuroblasts. Nature 402, 548–551 (1999).
pubmed: 10591217 doi: 10.1038/990135 pmcid: 10591217
Wodarz, A., Ramrath, A., Kuchinke, U. & Knust, E. Bazooka provides an apical cue for Inscuteable localization in Drosophila neuroblasts. Nature 402, 544–547 (1999).
pubmed: 10591216 doi: 10.1038/990128 pmcid: 10591216
Benton, R. & Johnston, D. S. A conserved oligomerization domain in Drosophila Bazooka/PAR-3 is important for apical localization and epithelial polarity. Curr. Biol. 13, 1330–1334 (2003).
pubmed: 12906794 doi: 10.1016/S0960-9822(03)00508-6 pmcid: 12906794
McGill, M. A., McKinley, R. F. & Harris, T. J. Independent cadherin-catenin and Bazooka clusters interact to assemble adherens junctions. J. Cell Biol. 185, 787–796 (2009).
pubmed: 19468069 pmcid: 2711589 doi: 10.1083/jcb.200812146
Wang, S. C. et al. Cortical forces and CDC-42 control clustering of PAR proteins for Caenorhabditis elegans embryonic polarization. Nat. Cell Biol. 19, 988–995 (2017).
pubmed: 28737772 doi: 10.1038/ncb3577
Rodriguez, J. et al. aPKC cycles between functionally distinct PAR protein assemblies to drive cell polarity. Dev. Cell 42, 400–415 (2017).
pubmed: 28781174 pmcid: 5563072 doi: 10.1016/j.devcel.2017.07.007
Dickinson, D. J., Schwager, F., Pintard, L., Gotta, M. & Goldstein, B. A single-cell biochemistry approach reveals PAR complex dynamics during cell polarization. Dev. Cell 42, 416–434 (2017).
pubmed: 28829947 pmcid: 5575849 doi: 10.1016/j.devcel.2017.07.024
Feng, W., Wu, H., Chan, L. N. & Zhang, M. The Par-3 NTD adopts a PB1-like structure required for Par-3 oligomerization and membrane localization. EMBO J. 26, 2786–2796 (2007).
pubmed: 17476308 pmcid: 1888665 doi: 10.1038/sj.emboj.7601702
Harris, T. J. C. Protein clustering for cell polarity: Par-3 as a paradigm. F1000Res. 6, 1620 (2017).
pubmed: 29026528 pmcid: 5583741 doi: 10.12688/f1000research.11976.1
Cheeks, R. J. et al. C. elegans PAR proteins function by mobilizing and stabilizing asymmetrically localized protein complexes. Curr. Biol. 14, 851–862 (2004).
pubmed: 15186741 doi: 10.1016/j.cub.2004.05.022 pmcid: 15186741
Slack, C., Overton, P. M., Tuxworth, R. I. & Chia, W. Asymmetric localisation of Miranda and its cargo proteins during neuroblast division requires the anaphase-promoting complex/cyclosome. Development 134, 3781–3787 (2007).
pubmed: 17933789 doi: 10.1242/dev.010900 pmcid: 17933789
Lu, B., Ackerman, L., Jan, L. Y. & Jan, Y. N. Modes of protein movement that lead to the asymmetric localization of partner of Numb during Drosophila neuroblast division. Mol. Cell 4, 883–891 (1999).
pubmed: 10635314 doi: 10.1016/S1097-2765(00)80218-X pmcid: 10635314
Mayer, B., Emery, G., Berdnik, D., Wirtz-Peitz, F. & Knoblich, J. A. Quantitative analysis of protein dynamics during asymmetric cell division. Curr. Biol. 15, 1847–1854 (2005).
pubmed: 16243032 doi: 10.1016/j.cub.2005.08.067 pmcid: 16243032
Patel, S. S., Belmont, B. J., Sante, J. M. & Rexach, M. F. Natively unfolded nucleoporins gate protein diffusion across the nuclear pore complex. Cell 129, 83–96 (2007).
pubmed: 17418788 doi: 10.1016/j.cell.2007.01.044 pmcid: 17418788
Ribbeck, K. & Gorlich, D. The permeability barrier of nuclear pore complexes appears to operate via hydrophobic exclusion. EMBO J. 21, 2664–2671 (2002).
pubmed: 12032079 pmcid: 126029 doi: 10.1093/emboj/21.11.2664
Chen, S. et al. Regulation of microtubule stability and organization by mammalian Par3 in specifying neuronal polarity. Dev. Cell 24, 26–40 (2013).
pubmed: 23273878 doi: 10.1016/j.devcel.2012.11.014 pmcid: 23273878
Ciuffa, R. et al. The selective autophagy receptor p62 forms a flexible filamentous helical scaffold. Cell Rep. 11, 748–758 (2015).
pubmed: 25921531 doi: 10.1016/j.celrep.2015.03.062 pmcid: 25921531
Gao, L. & Macara, I. G. Isoforms of the polarity protein par6 have distinct functions. J. Biol. Chem. 279, 41557–41562 (2004).
pubmed: 15292221 doi: 10.1074/jbc.M403723200 pmcid: 15292221
Patel, A. et al. A liquid-to-solid phase transition of the ALS protein FUS accelerated by disease mutation. Cell 162, 1066–1077 (2015).
pubmed: 26317470 doi: 10.1016/j.cell.2015.07.047 pmcid: 26317470
Murakami, T. et al. ALS/FTD mutation-induced phase transition of FUS liquid droplets and reversible hydrogels into irreversible hydrogels impairs RNP granule function. Neuron 88, 678–690 (2015).
pubmed: 26526393 pmcid: 4660210 doi: 10.1016/j.neuron.2015.10.030
Morais-de-Sa, E., Mirouse, V. & St Johnston, D. aPKC phosphorylation of Bazooka defines the apical/lateral border in Drosophila epithelial cells. Cell 141, 509–523 (2010).
pubmed: 20434988 pmcid: 2885938 doi: 10.1016/j.cell.2010.02.040
Wang, C., Shang, Y., Yu, J. & Zhang, M. Substrate recognition mechanism of atypical protein kinase Cs revealed by the structure of PKCiota in complex with a substrate peptide from Par-3. Structure 20, 791–801 (2012).
pubmed: 22579248 doi: 10.1016/j.str.2012.02.022 pmcid: 22579248
Spitaler, M., Villunger, A., Grunicke, H. & Uberall, F. Unique structural and functional properties of the ATP-binding domain of atypical protein kinase C-iota. J. Biol. Chem. 275, 33289–33296 (2000).
pubmed: 10906326 doi: 10.1074/jbc.M002742200 pmcid: 10906326
Zeng, M. et al. Reconstituted postsynaptic density as a molecular platform for understanding synapse formation and plasticity. Cell 174, 1172–1187 (2018).
pubmed: 30078712 doi: 10.1016/j.cell.2018.06.047 pmcid: 30078712
Buszczak, M. et al. The carnegie protein trap library: a versatile tool for Drosophila developmental studies. Genetics 175, 1505–1531 (2007).
pubmed: 17194782 pmcid: 1840051 doi: 10.1534/genetics.106.065961
Kono, K. et al. Reconstruction of Par-dependent polarity in apolar cells reveals a dynamic process of cortical polarization. Elife 8, e45559 (2019).
pubmed: 31172945 pmcid: 6555595 doi: 10.7554/eLife.45559
Oon, C. H. & Prehoda, K. E. Asymmetric recruitment and actin-dependent cortical flows drive the neuroblast polarity cycle. Elife 8, e45815 (2019).
pubmed: 31066675 pmcid: 6524966 doi: 10.7554/eLife.45815
Shan, Z. et al. Basal condensation of Numb and Pon complex via phase transition during Drosophila neuroblast asymmetric division. Nat. Commun. 9, 737 (2018).
pubmed: 29467404 pmcid: 5821850 doi: 10.1038/s41467-018-03077-3
Izumi, Y., Ohta, N., Itoh-Furuya, A., Fuse, N. & Matsuzaki, F. Differential functions of G protein and Baz-aPKC signaling pathways in Drosophila neuroblast asymmetric division. J. Cell Biol. 164, 729–738 (2004).
pubmed: 14981094 pmcid: 2172166 doi: 10.1083/jcb.200309162
Banani, S. F., Lee, H. O., Hyman, A. A. & Rosen, M. K. Biomolecular condensates: organizers of cellular biochemistry. Nat. Rev. Mol. Cell Biol. 18, 285–298 (2017).
pubmed: 28225081 doi: 10.1038/nrm.2017.7 pmcid: 28225081
Boeynaems, S. et al. Protein phase separation: a new phase in cell biology. Trends Cell Biol. 28, 420–435 (2018).
pubmed: 29602697 pmcid: 6034118 doi: 10.1016/j.tcb.2018.02.004
Shin, Y. & Brangwynne, C. P. Liquid phase condensation in cell physiology and disease. Science 357, 1253 (2017). eaaf4382.
doi: 10.1126/science.aaf4382
Hyman, A. A., Weber, C. A. & Julicher, F. Liquid-liquid phase separation in biology. Annu. Rev. Cell Dev. Biol. 30, 39–58 (2014).
pubmed: 25288112 doi: 10.1146/annurev-cellbio-100913-013325 pmcid: 25288112
Brangwynne, C. P. et al. Germline P granules are liquid droplets that localize by controlled dissolution/condensation. Science 324, 1729–1732 (2009).
pubmed: 19460965 doi: 10.1126/science.1172046 pmcid: 19460965
Strutt, H., Warrington, Samantha J. & Strutt, D. Dynamics of core planar polarity protein turnover and stable assembly into discrete membrane subdomains. Dev. Cell 20, 511–525 (2011).
Li, P. et al. Phase transitions in the assembly of multivalent signalling proteins. Nature 483, 336–340 (2012).
pubmed: 22398450 pmcid: 3343696 doi: 10.1038/nature10879
Wen, W. Phase separation in asymmetric cell division. Biochemistry 59, 47–56 (2020).
pubmed: 31617345 doi: 10.1021/acs.biochem.9b00813 pmcid: 31617345
Otwinowski, Z. & Minor, W. Processing of X-ray diffraction data collected in oscillation mode. Method Enzymol. 276, 307–326 (1997).
doi: 10.1016/S0076-6879(97)76066-X
McCoy, A. J. et al. Phasercrystallographic software. J. Appl. Crystallogr. 40, 658–674 (2007).
pubmed: 19461840 pmcid: 2483472 doi: 10.1107/S0021889807021206
Emsley, P. & Cowtan, K. Coot: model-building tools for molecular graphics. Acta Crystallogr. D Biol. Crystallogr. 60, 2126–2132 (2004).
pubmed: 15572765 doi: 10.1107/S0907444904019158 pmcid: 15572765
Adams, P. D. et al. PHENIX: a comprehensive Python-based system for macromolecular structure solution. Acta Crystallogr. D 66, 213–221 (2010).
pubmed: 20124702 doi: 10.1107/S0907444909052925 pmcid: 20124702
Lee, T. & Luo, L. Mosaic analysis with a repressible cell marker for studies of gene function in neuronal morphogenesis. Neuron 22, 451–461 (1999).
pubmed: 10197526 doi: 10.1016/S0896-6273(00)80701-1 pmcid: 10197526
Chai, P. C., Liu, Z., Chia, W. & Cai, Y. Hedgehog signaling acts with the temporal cascade to promote neuroblast cell cycle exit. PLoS Biol. 11, e1001494 (2013).
pubmed: 23468593 pmcid: 3582610 doi: 10.1371/journal.pbio.1001494
Gratz, S. J. et al. Highly specific and efficient CRISPR/Cas9-catalyzed homology-directed repair in Drosophila. Genetics 196, 961–971 (2014).
pubmed: 24478335 pmcid: 3982687 doi: 10.1534/genetics.113.160713

Auteurs

Ziheng Liu (Z)

Department of Neurosurgery, Huashan Hospital, the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China.

Ying Yang (Y)

Temasek Life Sciences Laboratory, Department of Biological Sciences, National University of Singapore, Singapore, 117604, Singapore.

Aihong Gu (A)

Department of Neurosurgery, Huashan Hospital, the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China.

Jiawen Xu (J)

Department of Neurosurgery, Huashan Hospital, the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China.

Ying Mao (Y)

Department of Neurosurgery, Huashan Hospital, the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China.

Haojie Lu (H)

Department of Neurosurgery, Huashan Hospital, the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China.

Weiguo Hu (W)

Department of Neurosurgery, Huashan Hospital, the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China.
Fudan University Shanghai Cancer Center and Cancer Metabolism Laboratory, Fudan University, Shanghai, 200032, China.

Qun-Ying Lei (QY)

Fudan University Shanghai Cancer Center and Cancer Metabolism Laboratory, Fudan University, Shanghai, 200032, China.

Zhouhua Li (Z)

College of Life Sciences, Capital Normal University, Beijing, 100048, China.

Mingjie Zhang (M)

Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.

Yu Cai (Y)

Temasek Life Sciences Laboratory, Department of Biological Sciences, National University of Singapore, Singapore, 117604, Singapore. caiyu@tll.org.sg.

Wenyu Wen (W)

Department of Neurosurgery, Huashan Hospital, the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China. wywen@fudan.edu.cn.

Articles similaires

[Redispensing of expensive oral anticancer medicines: a practical application].

Lisanne N van Merendonk, Kübra Akgöl, Bastiaan Nuijen
1.00
Humans Antineoplastic Agents Administration, Oral Drug Costs Counterfeit Drugs

Smoking Cessation and Incident Cardiovascular Disease.

Jun Hwan Cho, Seung Yong Shin, Hoseob Kim et al.
1.00
Humans Male Smoking Cessation Cardiovascular Diseases Female
Humans United States Aged Cross-Sectional Studies Medicare Part C
1.00
Humans Yoga Low Back Pain Female Male

Classifications MeSH