Freeze-fracture cytochemistry with polymyxin B. A study on the plasma membrane of uterine epithelial cells.

The peptide antibiotic polymyxin B, has been used as a label in a freeze-fracture cytochemical study of anionic phospholipids in the plasma membrane of uterine epithelial cells. The reagent produces mainly circular lesions visible on both P and E faces of fractured membranes. IMPs are found to be associated with lesions and we consider the possible association of integral membrane proteins with anionic phospholipids as well as the mechanisms of lesion formation.