Establishment of plasma membrane polarity involves numerous intracellular s
orting events. In the past few years, it has become apparent that there is
a subapical, non-Golgi compartment located in the hub of the sorting pathwa
ys involved. This 'subapical compartment', which probably consists of a het
erogeneous subset of functionally distinct domains related to endosomes, co
ntains some-well-characterized components involved in polarity-dependent so
rting and targeting of proteins and lipids. This article discusses the evid
ence supporting the existence of such a compartment, its biogenesis and its
role in cell polarity.