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SUMMARY:"Wnt signaling and stem cell control" by Prof. Roel Nusse
DTSTART:20090917T160000
DTSTAMP:20261005T001409Z
UID:d3ad2f0e111e9aabdc5426fc447ef4ebc4083f7b9181766fd7d2f01c
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Roel Nusse\, Department of Developmental Biology and How
 ard Hughes Medical Institute\, Stanford University\, USA\nAbstract\n\nIn m
 any contexts\, the self-renewal and differentiation of stem cells is influ
 enced by signals from their environment\, constituting a niche. It is post
 ulated that stem cells compete for local growth factors in the niche\, the
 reby maintaining a balance between the numbers of self-renewing and differ
 entiated cells. A critical aspect of the niche model for stem cell regulat
 ion is that the availability of self-renewing factors is limited and that 
 stem cells compete for these factors. Consequently\, the expression\, rang
 e and concentrations of the niche factors are critical importance. \n \nWe
  study the role of Wnt signaling and stem cells by purifying active Wnt pr
 oteins and applying them to cells and tissues\, thereby being able to asse
 ss the consequences of Wnt signaling in a direct way. Wnt proteins are mod
 ified by lipid attachment\, to make them hydrophobic in nature. We found t
 hat isolated Wnt proteins are active on a variety of stem cells\, includin
 g neural\, mammary and embryonic stem cells. In general\, Wnt proteins act
  to maintain the undifferentiated state of stem cells\, while other growth
  factors instruct the cells to proliferate. The combination of Wnts and th
 ose factors has allowed is to clonally expand and propagate stem cells in 
 an undifferentiated state for multiple passages. By subsequent in vivo tra
 nsplantation\, we find that the cells have retained their developmental po
 tential. \n \nDuring the diffusion and transport of the lipid-modified Wnt
  proteins between cells\, the interaction with a novel Wnt binding protein
 \, called SWIM\, may be essential in maintaining the solubility of Wnt\, a
 t least in Drosophila. 
LOCATION:SG 0211 https://plan.epfl.ch/?room==SG%0200211
STATUS:CONFIRMED
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