Title
Structural basis for mutation-induced destabilization of profilin 1 in ALS
Author
Sivakumar Boopathy, Tania V. Silvas, Maeve Tischbein, Silvia Jansen, Shivender M. Shandilya, Jill A. Zitzewitz, John E. Landers, Bruce L. Goode, Celia A. Schiffer, Daryl A. Bosco
Year
2015
Journal
PNAS
Abstract
Mutations in profilin 1 (PFN1) are associated with amyotrophic lateral sclerosis (ALS); however, the pathological mechanism of PFN1 in this fatal disease is unknown. We demonstrate that ALS-linked mutations severely destabilize the native conformation of PFN1 in vitro and cause accelerated turnover of the PFN1 protein in cells. This mutationinduced destabilization can account for the high propensity of ALSlinked variants to aggregate and also provides rationale for their reported loss-of-function phenotypes in cell-based assays. The source of this destabilization is illuminated by the X-ray crystal structures of several PFN1 proteins, revealing an expanded cavity near the protein core of the destabilized M114T variant. In contrast, the E117G mutation only modestly perturbs the structure and stability of PFN1, an observation that reconciles the occurrence of this mutation in the control population. These findings suggest that a destabilized form of PFN1 underlies PFN1-mediated ALS pathogenesis.
Full Article
Instrument
J-810
Keywords
Circular dichroism, Secondary structure, Biochemistry