Advances in understanding protein-lipid interactions through biophysical and bioelectronic approaches

Intrinsically disordered proteins (IDPs) are those that to do not possess a well-defined three dimensional structure. As a result, they show great flexibility when it comes to adopting a suitable conformation based on the target of interest. However, due to the nature of the free energy landscape with respect to protein folding, they can misfold and transform into toxic oligomeric or fibrillar species. In particular, this thesis focuses on a subset of IDPs, namely amyloid-beta 40 and 42, α-synuclein and Fused-in-Sarcoma. These proteins are implicated in the development and progression of neurodegenerative disorders such as Alzheimer’s Disease, Parkinson’s Disease, Amyotrophic Lateral Sclerosis and Frontotemporal Dementia respectively. The phenomenon of aggregation is seen to be the hallmark connecting the three IDPs, with multiple factors either accelerating or inhibiting the process. Currently, there is no cure for these disorders, therefore it becomes imperative to better understand the mechanisms behind their aggregation, so as to enable the development of therapeutics. This thesis focuses on understanding how these proteins interact with lipid molecules. Lipids form the majority component of the cell membrane. They are not just involved in maintaining the structural integrity of the plasma membrane, but are also involved in more complex processes such as signalling, regulation and intracellular transport. As the IDPs mentioned above are known to interact in the cytoplasmic space, it is interesting to characterise their interactions with lipids not just from a mechanistic standpoint, but also in terms of understanding their influence on subsequent aggregation or membrane disruption. To quantitatively characterise these protein-lipid interactions, we utilise a variety of biophysical approaches such as monitoring of aggregation kinetics, circular dichroism, transmission electron microscopy, microfluidic diffusional sizing and confocal microscopy. In our studies, we have aimed to incorporate natural membrane lipids in addition to the conventionally used synthetic lipids in order to increase the biological significance of our findings. We have also conceptualised a novel polymer-based bioelectronic device as a proof-of-concept to analyse membrane perturbations arising from the interaction of α-synuclein with anionic lipid membranes.

Name dc:type.qualificationname

Doctor of Philosophy (PhD)

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2023

Author dc:creator

• Kadgathur Jayaram, Akhila

Advisor dc:contributor.advisor

• Knowles, Tuomas

• Bioelectronics
• Biophysics
• Lipids
• Protein Aggregation

Licence

• https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/3e9dc78a-48c9-4097-a8a6-a90d541a73e3/download
• https://www.rioxx.net/licenses/all-rights-reserved/

Language dc:language

eng

DOI dc:identifier.doi

https://doi.org/10.17863/CAM.111152

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/372282