Misfolding and Amyloid Formation: Light Chain Associated Amyloidosis

Our overall goal in the lab is to understand molecular basis of disease. The amyloidoses are a group of protein misfolding diseases characterized by the accumulation of insoluble fibrillar protein that leads to cell death and tissue degeneration. Alzheimer's disease and the bovine spongiform encephalopathies are among the most well known amyloid diseases. Understanding the protein misfolding and aggregation mechanisms will help us to understand these diseases and will guide us to design therapeutic strategies to overcome the amyloid phenomenon.

Our laboratory will be applying physicochemical principles to study fibril formation. Light chain amyloidosis (AL) is an excellent model system to study amyloid diseases. As immunoglobulin chains, this family exhibits wide sequence diversity. Additionally, the deposition of monoclonal (Ig) light chains as amyloid fibrils affects several organs, causing dysfunction. The light-chain protein family presents a unique opportunity for comparative studies that might uncover patterns and points to the general mechanisms of amyloid formation, that will be very useful for other amyloid diseases.

A number of hypotheses have been put forth to explain why a given protein forms amyloid aggregates. One of these posits that a mutation in an amyloidogenic protein destabilizes the folded structure compared to native sequences. An alternative hypothesis suggests that the similarity among amyloidogenic proteins develops not at the level of their native folded structure, but arises from the intermediate conformations whose existence is usually transient. Yet a third hypothesis, which we wish to investigate is the role of protein folding kinetics and protein misfolding pathways in AL.

By exploring the role of folding kinetics, misfolding pathways, and stability, it will be possible to understand the mechanisms of amyloid formation in AL, leading to the prediction of the behavior of other AL variants, with the ultimate goal of intervening to prevent progression of the disease.