What drives an amyloid protein precursor from an amyloidogenic to a native-like aggregation pathway?

Conformational disorders such as Alzheimer’s, Parkinson’s, familial amyloidotic polyneuropathy and spongiform encephalopaties are a consequence of protein misfolding and aggregation predominantly in the form of amyloid fibrils. These pathologies represent a major health problem, which most probably will overwhelm the health systems of developed countries in the near future. Significant progress has been made recently to understanding the underlying mechanism of protein misfolding and aggregation. The current picture of protein aggregation is a phenomenon resulting from protein conformational fluctuations leading to misfolded intermediates prone to form non-native interactions with other intermediates, resulting in amyloid fibril formation. Fortunately just a small group of proteins are associated with human conformational disorders. The primary causes that lead this group of proteins to misfolding and aggregation are point mutations, protein over-expression and failure of protein quality-control system. Beside amyloid formation, there are other types of aggregation available to a misfold-disease-related polypeptide chain in the proteinfree energy landscape. Among them, native-like aggregation is becoming a widely studied topic of research.This aggregation type, simultaneously straightforward and ubiquitous, seems to be involved concurrently in the pathway of amyloid fibril formation and disruption. In this review, the pathways of misfold and aggregation of a protein are accessed along with the primary causes that turn a native soluble protein into amyloid fibrils or native-like aggregate. In addition, an insight into the biophysical and biochemical aspects fundamental to amyloid fibril formation and nativelike aggregation is provided. Finally some clues are presented about what makes a protein follow an amyloidogenic or native-like aggregation pathway.Conclusion: More laboratory data should be gathered about the structure, stability, dynamics and aggregation kinetics, in order to get a clearer picture of the biophysical mechanisms underlying native-like aggregation