Role of alpha-synuclein carboxy-terminus on fibril formation in vitro. Academic Article uri icon

abstract

  • Alpha-synuclein (alpha-syn) is the major component of intracellular inclusions in several neurodegenerative diseases, and the conversion of soluble alpha-syn into filamentous aggregates may contribute to disease pathogenesis. Since mechanisms leading to the formation of alpha-syn inclusions are unclear, in vitro models of alpha-syn aggregation may yield insights into this process. To that end, we examined the consequences on the progressive deletion of the carboxy-terminus of alpha-syn in regulating fibril formation, and we show here that carboxy-terminal truncated alpha-syn proteins aggregate faster than the full-length molecule. Protease digestion and immunoelectron microscopy indicate that the alpha-syn amino- and carboxy-termini are more solvent exposed than the central core and that filaments formed from carboxy-terminal truncated alpha-syn are narrower in diameter than the full-length molecule. Moreover, seeding experiments under conditions where full-length alpha-syn did not readily aggregate revealed that carboxy-truncated alpha-syn extending from amino acids 1-102 and 1-110 but not 1-120 were efficient in seeding full-length alpha-syn aggregation over a range of concentrations. Using site-directed mutagenesis, the negatively charged residues 104, 105 and 114, 115 in the carboxy-terminus were implicated in this reduced aggregation and the lack of seeding of full-length alpha-syn fibrillogenesis by 1-120. Our data support the view that the middle region of alpha-syn forms the core of alpha-syn filaments and that negative charges in the carboxy-terminus counteract alpha-syn aggregation. Thus, the carboxy-terminus of alpha-syn may regulate aggregation of full-length alpha-syn and determine the diameter of alpha-syn filaments.

published proceedings

  • Biochemistry

altmetric score

  • 10

author list (cited authors)

  • Murray, I., Giasson, B. I., Quinn, S. M., Koppaka, V., Axelsen, P. H., Ischiropoulos, H., Trojanowski, J. Q., & Lee, V.

citation count

  • 277

complete list of authors

  • Murray, Ian VJ||Giasson, Benoit I||Quinn, Shawn M||Koppaka, Vishwanath||Axelsen, Paul H||Ischiropoulos, Harry||Trojanowski, John Q||Lee, Virginia M-Y

publication date

  • July 2003