Aggregation of Lamin Protein in Aging and Disease


Pre-Clinical Research

Poster Number: T403


Alysia Vrailas-Mortimer, PhD, Oregon State University

Aging is a natural process that most organism experience. One gene that plays a role in aging is lamin, which when mutated can give rise to a variety of age-dependent diseases, including the accelerated aging disorder Hutchinson-Guilford Progeria. Though lamin is a nuclear envelope protein found in all cell types, specific mutations in lamin can give rise to tissue specific diseases such as the neuropathy, Charcot-Marie-Tooth disease (CMT), and muscular dystrophies such as Emery-Dreifuss Muscular Dystrophy (EDMD). As mutant forms of the lamin protein aggregate in these diseases, we tested what mechanism mediates the degradation of lamin during aging. Using the fruit fly Drosophila melanogaster model system, we find that during aging wildtype lamin is targeted for degradation by autophagy through an interaction with the p38 MAPK (p38Kb) and the co-chaperon starvin (stv, BAG-3 in mammalian systems). Interestingly, p38Kb is a regulator of aging and lifespan in flies, and we find that loss of p38Kb leads to accumulation of lamin and abnormally shaped nuclei with chromosomal leakage. We next tested if disease-causing mutations make lamin more aggregate prone, alter its ability to be targeted for degradation, and are associated with neuromuscular dysfunction. We find that different lamin mutations result in altered ratios of lamin protein species, in particular between the non-franesylated and farnesylated forms. In addition, we find differences in the aggregation of the different lamin mutant forms. Finally, we find that expression of these mutant forms results in impaired locomotor functions.