{"id":15,"date":"2019-05-07T13:25:36","date_gmt":"2019-05-07T13:25:36","guid":{"rendered":"https:\/\/dev.beta.embl.org\/groups\/cuylen\/index.php\/home\/"},"modified":"2021-03-09T17:51:13","modified_gmt":"2021-03-09T17:51:13","slug":"home","status":"publish","type":"page","link":"https:\/\/www.embl.org\/groups\/cuylen\/","title":{"rendered":"Home"},"content":{"rendered":"
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The Cuylen group investigates how proteins act as surfactants to regulate the spatial separation of chromosomes and other cellular organelles.<\/p>\r\n\n Edit<\/a>\n <\/div>\n <\/div>\n <\/div>\n
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\n \"image\n \n

\n Sara Cuylen-H\u00e4ring<\/a>\n <\/h3>\n \n

\n Group Leader\n <\/p>\n \n \n \n \n \n \n

\n ORCID:<\/span>\n \n 0000-0002-1193-4648\n <\/a>\n <\/p>\n \n Edit\n <\/a>\n <\/article>\n <\/div>\n\n <\/div>\n<\/div>\n\n\n\n

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Previous and current research<\/h3>\n\n\n\n

Eukaryotic cells are organised into compartments to coordinate \nbiochemical reactions in space and time. Many of these compartments, \ncommonly referred to as organelles, have membranes that generate a \nphysical barrier for macromolecules, such as proteins or nucleic acids. \nRemarkably, other organelles, for example the nucleolus, are not \nsurrounded by membranes. Recent studies have provided compelling \nevidence that membraneless organelles have liquid-like properties and \nundergo liquid de-mixing in a process called phase separation. Yet how \nthese membraneless organelles assemble and how they maintain their \nspatial separation is a central unresolved question in cell biology.<\/p>\n\n\n\n

The main interest of our group is the spatial organisation of \neukaryotic genomes. The genome of eukaryotes is divided into several \ndistinct chromosomes. During interphase, chromosomes are isolated from \nthe cytoplasm by a membrane, the nuclear envelope, and fill the entire \nnuclear space as loosely organised chromosome territories. However, upon\n entry into mitosis, chromosomes are compacted into thick fibres and are\n released into the cytoplasm after disassembly of the nuclear envelope. \nRemarkably, individual chromosomes remain separate entities during \nmitosis, whereas many other polymeric assemblies fuse with each other \nupon contact in a liquid-like manner. After more than a century of \nresearch, we still don\u2019t understand how chromosomes are kept as \nindividual bodies throughout mitosis.<\/p>\n\n\n\n

Our recent work has demonstrated that Ki-67, a chromosome surface \nprotein, enables mitotic chromosomes to move as independent mechanical \nbodies. In cells depleted of Ki-67, mitotic chromosomes coalesce into \none large chromosome mass, reminiscent of the tendency of other \nnon-membrane-bounded organelles to merge upon contact. Using genome \nengineering and advanced high-resolution live-cell imaging, we \ndiscovered that Ki-67 forms extended brush-like structures on the \nsurface of mitotic chromosomes, whose function in chromosome \nindividualisation depends on electrical charge and protein size. This is\n similar to surface-active agents (surfactants), chemical compounds used\n to maintain dispersions or emulsions, thus raising the exciting \npossibility that Ki-67 acts as a biological surfactant to disperse \nmitotic chromosomes.<\/p>\n\n\n\n

Future projects and goals<\/h3>\n\n\n\n

Our previous findings suggest that proteins can act as surfactants at\n the phase boundary between chromosomes and cytoplasm. We aim to further\n characterise the surfactant mechanism of Ki-67 and other synthetic \nsurfactant-like proteins in vitro<\/em> and in cells, and we will \nexplore whether other proteins act as surfactants at the liquid-liquid \ninterfaces of other membraneless organelles. We will use a highly \ninterdisciplinary approach that combines biochemical, biophysical and \ncell biological methods to advance our understanding of cellular \norganisation and biophysical properties of chromosomes.<\/p>\n\n<\/div>\n<\/div>\n\n\n

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\"Live-cell<\/a>
Figure 1:<\/strong> Live-cell imaging of Ki-67 (green) during the cell cycle reveals its re-localisation from nucleoli to the surface of mitotic chromosomes (magenta).<\/figcaption><\/figure>\n\n\n\n
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Figure 2:<\/strong> Model of Ki-67 function. Ki-67 (orange) forms brush-like structures on the surface of mitotic chromosomes to facilitate their spatial separation during cell division. (IMBA\/IMP graphics department)<\/figcaption><\/figure>\n\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"embl_taxonomy":[],"class_list":["post-15","page","type-page","status-publish","hentry"],"acf":[],"embl_taxonomy_terms":[],"_links":{"self":[{"href":"https:\/\/www.embl.org\/groups\/cuylen\/wp-json\/wp\/v2\/pages\/15","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.embl.org\/groups\/cuylen\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.embl.org\/groups\/cuylen\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.embl.org\/groups\/cuylen\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.embl.org\/groups\/cuylen\/wp-json\/wp\/v2\/comments?post=15"}],"version-history":[{"count":33,"href":"https:\/\/www.embl.org\/groups\/cuylen\/wp-json\/wp\/v2\/pages\/15\/revisions"}],"predecessor-version":[{"id":24035,"href":"https:\/\/www.embl.org\/groups\/cuylen\/wp-json\/wp\/v2\/pages\/15\/revisions\/24035"}],"wp:attachment":[{"href":"https:\/\/www.embl.org\/groups\/cuylen\/wp-json\/wp\/v2\/media?parent=15"}],"wp:term":[{"taxonomy":"embl_taxonomy","embeddable":true,"href":"https:\/\/www.embl.org\/groups\/cuylen\/wp-json\/wp\/v2\/embl_taxonomy?post=15"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}