How membrane characteristics influence membrane protein conformation
Cell membranes not only maintain cell integrity, but possibly also influence the functioning of membrane proteins. Local membrane order and cholesterol content are two important factors, but they remain poorly understood. Here, I have probed how the mode of interaction of Amylin (a disease causing peptide oligomer with high membrane affinity) is controlled by the nature of membrane. For this purpose, we have built a combined AFM-Confocal-FLIM-FCS set up and probed the accessibility of the terminals (N and C) and the extent of insertion in different membrane environments. We find that these parameters are highly dependent on the local lipid order. We also monitored the extent of depletion of cholesterol in presence and absence of amylin, and found that amylin resists the changes caused by cholesterol depletion and helps the membrane to retain its integrity. Thus, our study quantifies the strong reciprocal influence between membrane proteins and membranes, which has possible biological consequences.