The Role of STEP in Alzheimer's Disease

About the Research Project
Program
Award Type
Standard
Award Amount
$400,000
Active Dates
April 01, 2008 - March 31, 2011
Grant ID
A2008014
Goals
By using transgenic animal models of Alzheimer’s disease, this project seeks to test whether slowing down the activity of a particular molecular pathway can restore cognitive abilities.
Summary
Alzheimer’s disease is a devastating disease with few effective treatments. Understanding the molecular basis of this disease should lead the way to new therapies. We are testing the hypothesis that a protein called STEP disrupts communication between neurons in Alzheimer’s disease. STEP is a brain-specific protein that regulates the activity of several proteins required for the stabilization of memories. One of these proteins is the NMDA glutamate receptor. This receptor complex normally moves from intracellular pools to the neuronal surface where it can receive neurotransmitter signals required for the formation of long-term memories. The trafficking to and from membranes is a tightly regulated process, and STEP participates in this process. We recently discovered that STEP is inappropriately activated by beta amyloid. Moreover, active STEP removes NMDA receptors from neuronal surfaces. Inappropriate activation of STEP leads to loss of glutamate receptors and subsequent disruption to memory formation. We predict that reducing STEP activity will reduce the loss of NMDA receptors from their active sites. We will test this hypothesis by using an animal model of Alzheimer’s disease with reduced levels of STEP proteins. We predict these mice will be ‘rescued’ and have restored cognitive abilities. These findings will have potential therapeutic implications.
Progress Updates
Striatal Enriched tyrosine Phosphatase (STEP) is a protein that removes a phosphate group from glutamate receptor proteins (called NMDA) found on the surface of nerve cells, promoting their internalization. Drs. Paul Lombroso, Paul Greengard, and colleagues generated mice lacking STEP to understand this protein’s role in nerve cell communication breakdown and Alzheimer’s disease. These researchers found that reducing STEP activity reduced the internalization of NMDA receptors from their active sites on nerve cells. This retention of NMDA receptors appeared to rescue the cognitive deficits in Alzheimer’s disease mice. These exciting findings suggest new options for therapeutic interventions. As a result of the discoveries from this research grant, Drs. Lombroso and Greengard will design small molecule inhibitor drugs to decrease STEP activity and begin to test them in animal models of Alzheimer’s disease. Already, they have initiated a search for drug candidates in collaboration with the Laboratory for Drug Discovery at Harvard.
Grants
Related Grants
Alzheimer's Disease Research
Regulatory Mechanisms Underlying Endosomal Targeting of SORL1
Active Dates
January 01, 2025 - December 31, 2026
Principal Investigator
Olav Andersen, PhD
Regulatory Mechanisms Underlying Endosomal Targeting of SORL1
Active Dates
January 01, 2025 - December 31, 2026

Principal Investigator
Olav Andersen, PhD
Alzheimer's Disease Research
The Role of DYRK1A in Altered Microglia Biology in a Cellular Model of Alzheimer’s Disease in Down Syndrome
Active Dates
January 01, 2025 - December 31, 2027
Principal Investigator
Frances Wiseman, PhD
The Role of DYRK1A in Altered Microglia Biology in a Cellular Model of Alzheimer’s Disease in Down Syndrome
Active Dates
January 01, 2025 - December 31, 2027

Principal Investigator
Frances Wiseman, PhD
Alzheimer's Disease Research
Synergistic Effects of Biological Sex and Sleep Loss in an AD Mouse Model
Active Dates
January 01, 2025 - December 31, 2026
Principal Investigator
Mallar Chakravarty, PhD
Synergistic Effects of Biological Sex and Sleep Loss in an AD Mouse Model
Active Dates
January 01, 2025 - December 31, 2026
Principal Investigator
Mallar Chakravarty, PhD