Exploring the occurrence of thioflavin-T-positive insulin amyloid aggregation intermediates

Mantas Ziaunys; Andrius Sakalauskas; Kamile Mikalauskaite; Vytautas Smirnovas

doi:10.7717/peerj.10918

Exploring the occurrence of thioflavin-T-positive insulin amyloid aggregation intermediates

PeerJ. 2021 Feb 10:9:e10918. doi: 10.7717/peerj.10918. eCollection 2021.

Authors

Mantas Ziaunys¹, Andrius Sakalauskas¹, Kamile Mikalauskaite¹, Vytautas Smirnovas¹

Affiliation

¹ Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania.

Abstract

The aggregation of proteins is considered to be the main cause of several neurodegenerative diseases. Despite much progress in amyloid research, the process of fibrillization is still not fully understood, which is one of the main reasons why there are still very few effective treatments available. When the aggregation of insulin, a model amyloidogenic protein, is tracked using thioflavin-T (ThT), an amyloid specific dye, there is an anomalous occurrence of double-sigmoidal aggregation kinetics. Such an event is likely related to the formation of ThT-positive intermediates, which may affect the outcome of both aggregation kinetic data, as well as final fibril structure. In this work we explore insulin fibrillization under conditions, where both normal and double-sigmoidal kinetics are observed and show that, despite their dye-binding properties and random occurrence, the ThT-positive intermediates do not significantly alter the overall aggregation process.

Keywords: Aggregation intermediates; Amyloid aggregation; Double-sigmoidal kinetics; Insulin aggregation; Thioflavin-T.

Grants and funding

This research is funded by Vilnius University, grant No. MSF-JM-3. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.