Preventing Alzheimers from developing is a goal of Raphael Kopan, Ph.D., professor of molecular biology and pharmacology at the Washington University School of Medicine. The moss plant (Physcomitrella patens) studied in the laboratory of Ralph S. Quatrano, Ph.D., Spencer T. Olin Professor and chair of the WUSTL biology department on the Danforth Campus, might inch Kopan toward that goal. Heres how.
The gene presenilin in mammals provides the catalytic activity for an enzyme called gamma secretase, which cleaves, or cuts, important proteins Notch, Erb4 and the amyloid precursor protein (APP), all key components of communication channels that cells use to arbitrate functions during development. Two genes occur in mammals in which mutations cause an earlier onset of Alzheimers. One is APP, where a fragment of the protein accumulates in amyloid plaques, associated with the disease. Another common site for mutations is found in presenilin (PS) proteins. The enzyme gamma secretase contains PS and works to dispose of proteins stuck in the cellular membrane.
This enzyme with PS at its core mediates two cellular decisions. One is to cut APP and as a byproduct, generate the bad peptide associated with Alzheimers; the other is to cut the Notch protein in response to specific stimuli. Notch is then free to enter the nucleus of cells where it partakes in regulating normal gene expression. Without Notch activity, a mammal has no chance of living.
Notch is a part of short-range mammalian communication channel, and for years it has been known to have a working relationship with PS. However, Notch is absent in plant cells, and presenilin function in plants remained mysterious until Quatranos post-doctoral researcher, Abha Khandelwal, Ph.D., arrived at Washington University and was interested in understanding signal transduction in plants.
When I searched the literature, the plant signal transduction pathways were not very well do
|Contact: Tony Fitzpatrick|
Washington University in St. Louis