Fig. 5.

Control membranes illustrate the selective association of Hsp70-1A with DPPS. a Representative overview and zoom-in images of a DOPC/DOPS 80:20 bilayer after incubation with 0.5 μg/ml Hsp70-1A for 30 min. Like all other samples, the bilayer was gently washed after incubation to remove unbound protein. Imaging then revealed the absence of Hsp70-1A all over the sample. Note the vertical range of 2 nm in the overview image and 1 nm in the small scan area image. This lipid mixture does not segregate at ambient temperature, but remains in a mixed disordered phase with a smooth topography. b A DOPC/eSM/chol 40:40:20 bilayer crudely approximates the extracellular leaflet of a eukaryotic cell. This model membrane typically separates into domains of eSM- and cholesterol-rich Lo phase in a ‘sea’ of cholesterol-depleted DOPC-rich Ld phase. Incubation with 0.5 μg/ml Hsp70-1A for 30 min was followed by gentle washing steps. The zoom-in scan shows very few molecules that associated only non-specifically with both Lo and Ld