Related Experiment Video
Updated: Feb 6, 2026
Protein Modifications: Protein Kinases and Phosphatases
Asymmetric and symmetric stem-cell divisions in development and cancer
Sean J Morrison1, Judith Kimble
1Howard Hughes Medical Institute and Life Sciences Institute, Department of Internal Medicine, and Center for Stem Cell Biology, University of Michigan, Ann Arbor, Michigan 48109-2216, USA. seanjm@umich.edu
Abstract:
Much has been made of the idea that asymmetric cell division is a defining characteristic of stem cells that enables them to simultaneously perpetuate themselves (self-renew) and generate differentiated progeny. Yet many stem cells can divide symmetrically, particularly when they are expanding in number during development or after injury. Thus, asymmetric division is not necessary for stem-cell identity but rather is a tool that stem cells can use to maintain appropriate numbers of progeny. The facultative use of symmetric or asymmetric divisions by stem cells may be a key adaptation that is crucial for adult regenerative capacity.
Related Concept Videos
Protein Kinases and Phosphatases
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Regulated Protein Degradation
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
Covalently Linked Protein Regulators
These groups modify specific amino acids in a protein....
Co-activators and Co-repressors
Activation Energy
Activation and Inactivation of G Proteins