Kai Simons

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Kai Simons
Prof Kai Simons 2014 (cropped).jpg
Born (1938-05-24) 24 May 1938 (age 84)
EducationUniversity of Helsinki (MD), Rockefeller University (postdoctoral fellowship)
Known forlipid rafts, trans-Golgi network
SpouseCarola Simons
Children3; including Mikael and Matias
Scientific career
Fieldsbiochemistry, cell biology
InstitutionsRockefeller University, University of Helsinki, EMBL, MPI-CBG, Lipotype GmbH
InfluencedSuzanne Eaton

Kai Simons (born 24 May 1938) is a Finnish professor of biochemistry and cell biology and physician living and working in Germany. He introduced the concept of lipid rafts,[1] as well as coined the term trans-Golgi network and proposed its role in protein and lipid sorting.[2] The co-founder and co-organizer of EMBO, ELSO, Simons initiated the foundation of MPI-CBG,[3] where he acted as a director (1998–2006) and a group-leader (until 2012).[4][5] He is the co-founder and co-owner of Lipotype GmbH.[6]


Kai Simons is the son of a physics professor. His father convinced him to study medicine, though he originally wanted to study physics.[3] While studying at the University of Helsinki, Simons spent a summer internship in the Stockholm laboratory of Bengt Samuelsson[7] There, he studied mechanisms of vitamin B12 absorption.[3] He worked with other students to organize a campaign to fight taeniasis, a disease common in eastern Finland where eating raw fish is popular.[7]

After completing his MD in 1964, he began a postdoctoral fellowship at Rockefeller University in New York City where he worked between 1966 and 1967 on blood serum protein polymorphism.[3] He returned to Helsinki in 1967, where he began working as a Junior Investigator for the Finnish Medical Research Council at the University of Helsinki.[7][8] He became a group leader in 1972 and was a biochemistry professor in 1971–79 at the medical faculty of this university[8] At first, he continued his work on serum proteins. Next, together with Leevi Kääriäinen and Ossi Renkonen, he started a research team – later joined by Ari Helenius, his first PhD student and later a post doctoral researcher who became Simons' brother-in-law. After a one-month stay in MRC Laboratory for Molecular Biology in Cambridge, the group started investigating a Semliki Forest virus, introduced to Simons by Kääriäinenem.[3]

In 1975 Simons came to Heidelberg (Germany), as one of the EMBL group leaders. Together with Ari Helenius he helped to develop EMBL, headed at this time by John Kendrew.[3] In years 1982–1998 Simons was a coordinator of the Cell Biology Program there.[8] During this time he for the first time presented the concept of lipid rafts.

In 1999 he took part in setting up ELSO (later incorporated into EMBO), which later he presided over.[9]

He was one of the initiators of establishing and building Max Planck Institute of Molecular Cell Biology and Genetics in Dresden (Germany), where he moved. Formally from 1998 (beginning of MPI-CBG construction) and practically from 2000 he was one of five institute's directors and also a group leader there[4][5] Since 2006 he is a director emeritus.[4]

In 2012 he started-up a biotech company Lipotype GmbH, where he is a CEO.[6]

He is married to Carola Simons and a father of three: twins – Mikael (neurobiologist) and Katja (sociologist), and the youngest of three, Matias (physician).[7]


Early in his career, Kai Simons pursued research in the field of medical biochemistry. Both his master's thesis and postgraduate research focused on vitamin B12 absorption.[3][10][11] After returning from his post-doc scholarship he continued research on vitamin B12 as well as on blood plasma proteins, but soon started investigating Semliki Forest virus, focusing on its membrane and its lipid composition and their role in the virus budding and its transport, as the model for lipid and protein secretion.[3][12][13][14][15] During this period, Simons also investigated the application of detergents in biochemistry with a special attention to their role in biological membrane research.[16]

The virus lifecycle and how it uses components of vesicular pathways while shuttling to the cell surface, turned Simons' attention toward vesicular transport pathways and cell polarization. Applying epithelial model cellsMDCK (Madin-Darby canine kidney), he investigated lipid transport, protein sorting and their role in polarizing cells.[3][17][18]

In these studies, he described the role of the trans-Golgi network (TGN) in protein and lipid sorting according to their destination.[2][3] In his works from 1988, together with Gerit van Meer,[19][20] Simons proposed the existence of lipid microdomains in cell membranes for the first time.[3] Such microdomains differ in their composition from the surrounding membrane and have special functions. Simons coined the term 'lipid rafts' to describe these microdomains. This concept was developed over the years to be presented more fully in 1997 in Nature journal by Simons and Ikonen.[1] This paper became one of the most frequently cited works in the field of membrane research. Other Simons' paper, on role of lipid rafts in the signal transduction[21] is second highest cited work and Simons is fourth highest cited scientist in the field of signal transduction. Kai Simons was also recognized by ISI Web of Knowledge, as one of the most cited scientist ever.

In subsequent years, Simons continued to work on the role of lipid rafts, and more generally lipids, in cell polarization and protein sorting.[22] He was interested also in the role of lipids and protein sorting in neurodegenerative diseases, especially in Alzheimer's disease.[23][24]

His scientific record includes more than 350 scientific articles, mostly in the field of biochemistry, molecular organization of the cell, and biochemistry and physiology of a cell membrane.

Considering his work from years 1996–2007 tracked until May 2009, Simons was 12. in the list of the most frequently cited scientists in the field cell biology with 90 articles and 16,299 citations.[25]

Honours and awards[edit]

Kai Simons honours and awards include:[8][26]

Kai Simons was and is also a member of numerous societies, committees and organisations, as well as an editor for several scientific journals.[8]


  1. ^ a b Simons K, Ikonen E (1997). "Functional rafts in cell membranes". Nature. 387 (6633): 569–72. Bibcode:1997Natur.387..569S. doi:10.1038/42408. PMID 9177342. S2CID 4359503.
  2. ^ a b Griffiths G, Simons K (1986). "The trans Golgi network: sorting at the exit site of the Golgi complex". Science. 234 (4775): 438–43. Bibcode:1986Sci...234..438G. doi:10.1126/science.2945253. PMID 2945253.
  3. ^ a b c d e f g h i j k Simons, Kai (29 December 2008). "Kai Simons: membrane master". The Journal of Cell Biology. 183 (7): 1180–1181. doi:10.1083/jcb.1837pi. ISSN 1540-8140. PMC 2606959. PMID 19114590.
  4. ^ a b c "MPI-CBG: Directors". Max Planck Institute of Molecular Cell Biology and Genetics. Retrieved 26 July 2016.
  5. ^ a b "MPI-CBG: Alumni". Max Planck Institute of Molecular Cell Biology and Genetics. Retrieved 26 July 2016.
  6. ^ a b "Everything you should know ABOUT US". Lipotype GmbH. Retrieved 26 July 2016.
  7. ^ a b c d "ASCB Members Profile Archives – Kai Simons". The American Society for Cell Biology. 13 August 2009. Archived from the original on 15 July 2007. Retrieved 27 July 2016.
  8. ^ a b c d e "Kai Simons". MPI CBG Research Group -: Group Leader. Max Planck Institute of Molecular Cell Biology and Genetics. Archived from the original on 27 September 2016. Retrieved 28 July 2016.
  9. ^ Gransalke, Kathleen (2014). "There Are No Easy Solutions" (PDF). Lab Times. 4: 34–37. ISSN 1864-2381. Archived from the original (PDF) on 6 August 2016. Retrieved 27 July 2016.
  10. ^ Grasbeck, R.; Runeberg, L.; Simons, K. (12 December 1959). "Intrinsic factor and radiovitamin B12 excretion in rats". Acta Physiologica Scandinavica. 47: 370–374. ISSN 0001-6772. PMID 13828995.
  11. ^ Grasbeck, R.; Simons, K.; Sinkkonen, I. (1 January 1962). "Purification of intrinsic factor and vitamin B12 binders from human gastric juice". Annales Medicinae Experimentalis et Biologiae Fenniae. 40(Suppl 6): 1–24. ISSN 0003-4479. PMID 13949889.
  12. ^ Renkonen O, Gahmberg CG, Kaariainen L, Simons K (1972). "Envelope of Semliki Forest virus as membrane model". Biochem. J. 128 (1): 20P–21P. doi:10.1042/bj1280020pb. PMC 1173622. PMID 5085567.
  13. ^ Renkonen O, Kääriäinen L, Gahmberg CG, Simons K (1972). "Lipids of Semliki Forest virus and of host cell membranes". Biochem. Soc. Symp. (35): 407–22. PMID 4614812.
  14. ^ Simons K, Garoff H (1980). "The budding mechanisms of enveloped animal viruses". J. Gen. Virol. 50 (1): 1–21. doi:10.1099/0022-1317-50-1-1. PMID 6255080.
  15. ^ Simons K, Warren G (1984). "Semliki Forest virus: a probe for membrane traffic in the animal cell". Adv. Protein Chem. Advances in Protein Chemistry. 36: 79–132. doi:10.1016/S0065-3233(08)60296-X. ISBN 9780120342365. PMC 7173159. PMID 6382965.
  16. ^ Helenius A, Simons K (1975). "Solubilization of membranes by detergents". Biochim. Biophys. Acta. 415 (1): 29–79. doi:10.1016/0304-4157(75)90016-7. PMID 1091302.
  17. ^ Simons K, Fuller SD (1985). "Cell surface polarity in epithelia". Annu. Rev. Cell Biol. 1: 243–88. doi:10.1146/annurev.cb.01.110185.001331. PMID 3939606.
  18. ^ Simons K (1987). "Membrane traffic in an epithelial cell line derived from the dog kidney". Kidney Int. Suppl. 23: S201–10. PMID 2831424.
  19. ^ van Meer G, Simons K (1988). "Lipid polarity and sorting in epithelial cells". J. Cell. Biochem. 36 (1): 51–8. doi:10.1002/jcb.240360106. hdl:1874/294292. PMID 3277985. S2CID 32086669.
  20. ^ Simons K, van Meer G (1988). "Lipid sorting in epithelial cells". Biochemistry. 27 (17): 6197–202. doi:10.1021/bi00417a001. hdl:1874/293951. PMID 3064805.
  21. ^ Simons, K.; Toomre, D. (1 October 2000). "Lipid rafts and signal transduction". Nature Reviews. Molecular Cell Biology. 1 (1): 31–39. doi:10.1038/35036052. ISSN 1471-0072. PMID 11413487. S2CID 10914632.
  22. ^ Klemm, Robin W.; Ejsing, Christer S.; Surma, Michal A.; Kaiser, Hermann-Josef; Gerl, Mathias J.; Sampaio, Julio L.; de Robillard, Quentin; Ferguson, Charles; Proszynski, Tomasz J. (18 May 2009). "Segregation of sphingolipids and sterols during formation of secretory vesicles at the trans-Golgi network" (PDF). The Journal of Cell Biology. 185 (4): 601–612. doi:10.1083/jcb.200901145. ISSN 1540-8140. PMC 2711577. PMID 19433450.
  23. ^ Rajendran, Lawrence; Honsho, Masanori; Zahn, Tobias R.; Keller, Patrick; Geiger, Kathrin D.; Verkade, Paul; Simons, Kai (25 July 2006). "Alzheimer's disease beta-amyloid peptides are released in association with exosomes". Proceedings of the National Academy of Sciences of the United States of America. 103 (30): 11172–11177. Bibcode:2006PNAS..10311172R. doi:10.1073/pnas.0603838103. ISSN 0027-8424. PMC 1544060. PMID 16837572.
  24. ^ Rajendran, Lawrence; Schneider, Anja; Schlechtingen, Georg; Weidlich, Sebastian; Ries, Jonas; Braxmeier, Tobias; Schwille, Petra; Schulz, Jörg B.; Schroeder, Cornelia (25 April 2008). "Efficient inhibition of the Alzheimer's disease beta-secretase by membrane targeting". Science. 320 (5875): 520–523. Bibcode:2008Sci...320..520R. doi:10.1126/science.1156609. ISSN 1095-9203. PMID 18436784. S2CID 5500387.
  25. ^ Neumann, Ralf (2009). "Publication Analysis 1996–2007. Cell Biology" (PDF). Lab Times. 5: 42–44. ISSN 1864-2381. Retrieved 27 July 2016.
  26. ^ "Academy of Europe: Simons, Kai". Academia Europaea. Retrieved 26 July 2016.
  27. ^ "Kai Simons. Robert Koch Gold Medal 2016". Robert Koch Gold Medal 2016. Robert-Koch-Stiftung. 2016. Retrieved 26 July 2016.

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