RESEARCH

Protein phosphorylation is a post-translational modification in which a phosphate group is attached to a protein by an enzyme termed a "protein kinase".  This addition can affect the protein's structure, function and/or localization and thus impact its role(s) within the cell.  The activity of protein kinases is counteracted by enzymes termed "protein phosphatases", which remove the phosphatate group.  It is the balance of these 2 activities that determines the net phosphorylation state of a protein at any given time.

Paradigm that dominated early research on regulated protein phosphorylation:

Protein kinases are activated by external signals such as hormones to phosphorylate intracellular enzymes and activate physiological responses. 

Return to the basal state was believed to involve poorly defined and relatively nonspecific protein phosphatases, whose activity was constant and not regulated. 

 

Phosphatases were referred to as “housekeeping enzymes” and “physiologically uninteresting.”

Research by several groups over the years proved this spectacularly wrong, with protein phosphatases shown to be subject to regulation just like their kinase counterparts.  

Aberrant protein phosphorylation is linked to many human diseases, and protein kinases are currently the second largest drug target for the pharmaceutical industry. Targeting protein phosphatases offers another therapeutic option, and the method of their regulation suggests that this targeting has the capacity to be even more specific (i.e. fewer off-target effects).

Our work focuses primarily on the contribution of the serine/threonine phosphatase PP1 (Protein Phosphatase 1) to the regulation of a wide-range of cellular pathways, including nuclear organization, ribosome biogenesis, DNA damage sensing and repair and response to stress.

Research generously supported by:

Department of Cellular & Molecular Medicine

Ottawa Institute of Systems Biology

University of Ottawa

Ottawa, Canada

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