AP-1 and retromer play opposite roles in the trafficking of sortilin between the Golgi apparatus and the lysosomes.
Sortilin has been implicated in the sorting of one soluble hydrolase and two sphingolipid activator proteins to the lysosomes. While the GGA adaptor proteins have been demonstrated to play a role in the targeting of sortilin to the endosomes, the recycling of sortilin has not yet been elucidated. Here we examine the role of two adaptor protein complexes, AP-1 and retromer. Our results demonstrate that AP-1 is required for the transport of sortilin to the endosomes and retromer for the recycling of sortilin to the Golgi apparatus. While inhibition of AP-1 causes accumulation of sortilin in the Golgi apparatus, RNAi depletion of retromer results in retention of sortilin in the lysosomes. We also demonstrate that the interaction of sortilin with retromer occurs through a YXXPhi site in its cytosolic tail. In conclusion, our observations indicate that retromer and AP-1 play opposite roles in the trafficking of sortilin.
Canuel
Maryssa
M
Department of Anatomy and Cell Biology, McGill University, 3640 University Street, Montreal, Que., Canada.
Lefrancois
Stephane
S
Zeng
Jibin
J
Morales
Carlos R
CR
D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D006056:Golgi Apparatus / Q000378:metabolism*; D008247:Lysosomes / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology*; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D000099183:Sortilin
D033942:Adaptor Proteins, Vesicular Transport; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D018808:Transcription Factor AP-1; D000099183:Sortilin