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.
apicolateral plasma membrane
basal plasma membrane +
basolateral plasma membrane
caveola neck
cell body membrane +
cell projection membrane +
cell trailing edge membrane +
cellular bud membrane
cellularization cleavage furrow +
cleavage furrow +
cornified envelope
cytoplasmic side of apical plasma membrane
cytoplasmic side of plasma membrane +
cytoproct
cytostome
external side of apical plasma membrane
external side of plasma membrane +
extrinsic component of plasma membrane +
growth cone membrane
hinge region between urothelial plaques of apical plasma membrane