Endothelial Cell Membranes: Polarity of Particles as Seen by Freeze-Fracturing

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Science  12 Jan 1973:
Vol. 179, Issue 4069, pp. 190-192
DOI: 10.1126/science.179.4069.190


Freeze-fracturing shows particles within membranes. In plasma membranes of most cells the particles are more strongly bound to the inner half. In unfixed endothelial cells, this polarity is reversed. Glutaraldehyde fixation results in conventional polarity. The reverse polarity may be related to a mechanism for preferential fusion of pinocytotic vesicles with the plasma membrane.