Figure 9.

The Egr-1-agrin pathway may aid in the understanding of synaptic homeostatic mechanisms at the NMJ, which occur during the process of normal aging, as well as in the age-related condition known as sarcopenia. Reduction of Egr-1 expression leads to increased expression and cleavage of agrin in both brain and muscle as well as NMJ abnormalities, many of which are consistent with and reflective of aging and sarcopenia. Thus, dysregulation of the Egr-1-agrin pathway may provide a novel model system to study synaptic homeostasis at the NMJ, and Egr-1 deficient mice may serve as a suitable model to elucidate mechanisms associated with the underlying physiology of aging.