Cellular component

asymmetric unit membrane

A scallop-shaped plaque, also referred to as an asymmetric unit membrane (AUM), found in the apical plasma membrane of urothelial superficial (umbrella) cells which form a a barrier to the passage of water and soluble toxic compounds found in urine. The plaques are thickened regions of membrane composed of uroplakin transmembrane proteins which form a crystalline array.

AUM