Researchers identify protein essential for cell division in blood-forming stem cells
04 December 2010
University of Michigan researchers have discovered that a protein known to regulate cellular metabolism is also necessary for normal cell division in blood-forming stem cells. Loss of the protein results in an abnormal number of chromosomes and a high rate of cell death.
The finding demonstrates that stem cells are metabolically different from other blood-forming cells, which can divide without the protein, Lkb1. This metabolic difference could someday be used to better control the behavior of blood-forming stem cells used in disease treatments, said Sean Morrison, director of the U-M Center for Stem Cell Biology, which is based at the Life Sciences Institute.
"This raises the possibility that, in the future, we may be able to modulate stem cell function --when treating degenerative diseases or when performing cell therapies-by altering the metabolism of the cells," said Morrison, a Howard Hughes Medical Institute investigator. "It opens up a whole new area of inquiry that, until now, had not been recognized."
Lkb1 is a protein kinase that acts as a tumour suppressor and coordinates cellular metabolism with cell growth. Specifically, Lkb1 (and another kinase called AMPK) helps maintain a balance between a cell's internal energy production and the process of cell division, sending signals to halt division when a cell lacks the energy needed to execute the process.
Few studies have examined stem cell metabolism. There's been a widespread assumption among biologists that basic metabolic processes are broadly similar in most cell types.
In many types of cells, deleting the genes that make Lkb1 and AMPK leads to tissue overgrowth and the formation of tumors, presumably because the cells no long receive signals telling them to stop dividing.