Nov 1, 1989

Intestinal crypt stem cells possess high levels of cytoskeletal-associated phosphotyrosine-containing proteins and tyrosine kinase activity relative to differentiated enterocytes

The Journal of Cell Biology
D R BurgessW H Kinsey


Growth and differentiation of stem cells is thought to be regulated by growth factors and responding protein tyrosine kinase activities. Comparing mitotic stem cells from the adult intestinal epithelium, isolated from the crypts of Lieberkuhn, with isolated differentiated absorbtive cells we find major differences in the levels of phosphotyrosine-containing proteins. Crypt stem cells possess two major phosphotyrosine-containing polypeptides of 36 and 17 kD which have greater than 15 times more phosphotyrosine than that present in the polypeptides of differentiated enterocytes. Tyrosine kinase activity and similar phosphotyrosine-containing proteins are associated with the Triton cytoskeleton. Moreover, crypt tyrosine kinase(s) is active in vitro in phosphorylating similar cytoskeleton-associated substrates. These results suggest that cytoskeleton-associated phosphotyrosine kinase(s) and their substrates may play a role in growth and differentiation of adult intestinal epithelial cells.

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Mentioned in this Paper

Squamous Transitional Epithelial Cell Count
Triton preparation
Structure of Intestinal Gland
Cell Differentiation Process
Growth Factor
Structure of Intestinal Epithelium
Epithelial Cell Count (Procedure)
Epithelial Cells

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