MEMBRANE PROTEIN TRAFFICKING IN THE ENDOCYTIC PATHW A Y

INTRODUCTION . . . . . . . . . . . . . . . . . .. . . . . .. . . . . . .. . . . . . . . . . . 129 COMPARTMENTS WITHIN THE ENDOCYTIC PATHWAY . . . . . . . . . . . . . . 1 3 1 Recycling Pathway between the Cell Surface and the Endosome . .... .... . 1 3 1 Sorting Endosome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 33 Recycling Endosome . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 33 Endosome Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 34 Fate of Sorting Endosomes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 34 Direct Entry into the Endocytic Pathway from the Golgi Complex ... . . . ... 1 35 SORTING SIGNALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 37 Internalization Signals of Recycling Receptors . . . . . . . . . . . . . . . . . . . . . . 1 37 Internalization Signals are Tight Turns .. .. . . ... .. . . .. .. . . . . .... 144 Intracellular Sorting Signals ..... .. . .. .... . . ..... . . . .. . .... . . 146 Modulation of Sorting Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 MOLECULAR SORTING MACHINERY . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 50 CONCLUDING REMARKS 155