Self-replicating protein conformations and information transfer: The adaptive β-sheet model

The deposition of proteins with a highly ordered β-sheet conformation is characteristic of several amyloid diseases. However, recent data indicate that amyloid formation is not always pathological, but may also be physiological. Based on the new insights in understanding the structural arrangements and the self-propagating properties of the β-conformational proteins in combination with the progress in elucidating the mechanisms of prion genetics and chaperone-controlled protein folding, a model of an adaptive β-sheet information system was developed. The idea is advanced that exogenous information can be specifically stored in the protease-resistant β-sheet rich protein aggregates in a prion-like mode creating a cytoplasmic molecular memory. The conformationally-bound information can then be transmitted to next cell generations by way of the self-propagating potential of the amyloidogenic structure. Controlled by a network of input-sensitive molecular chaperones, the β-conformation based information system could constitute a form of soft inheritance characterized by adaptability and plasticity. It is suggested that the β-system represents an evolutionary conserved primordial inheritance mechanism based on protein conformation.