PROTEIN SORTING IN THE GOLGI-COMPLEX

Even after one hundred years, the Golgi apparatus remains a major chal lenge in the field of Cell Biology. This is particularly true in terms of transport and of protein sorting. For example, the question how ca rgo proteins are transported through this organelle is still a matter of debate. Emphasis has been put on the role of anterograde and retrog rade transport vesicles. These have been proposed to carry cargo from cisterna to cisterna and to recycle components needed for further roun ds of transport. Alternatively, anterograde movement of cargo takes pl ace in cisternal membranes rather than transport vesicles. These membr anes assemble and mature in a cis to trans direction. In this case, re trograde transport vesicles need to recycle all components of the Golg i apparatus and this demands a highly dynamic and efficient sorting ma chinery. Here we will discuss possible mechanisms for protein sorting in the context of cisternal maturation and propose that a common mecha nism is sufficient to explain both transport of cargo and sorting of r esident proteins. (C) 1998 Elsevier Science B.V. All rights reserved.