The cargo receptors Surf4, endoplasmic reticulum-Golgi intermediate compartment (ERGIC)-53, and p25 are required to maintain the architecture of ERGIC and Golgi.
Rapidly cycling proteins of the early secretory pathway can operate as cargo receptors. Known cargo receptors are abundant proteins, but it remains mysterious why their inactivation leads to rather limited secretion phenotypes. Studies of Surf4, the human orthologue of the yeast cargo receptor Erv29p, now reveal a novel function of cargo receptors. Surf4 was found to interact with endoplasmic reticulum-Golgi intermediate compartment (ERGIC)-53 and p24 proteins. Silencing Surf4 together with ERGIC-53 or silencing the p24 family member p25 induced an identical phenotype characterized by a reduced number of ERGIC clusters and fragmentation of the Golgi apparatus without effect on anterograde transport. Live imaging showed decreased stability of ERGIC clusters after knockdown of p25. Silencing of Surf4/ERGIC-53 or p25 resulted in partial redistribution of coat protein (COP) I but not Golgi matrix proteins to the cytosol and partial resistance of the cis-Golgi to brefeldin A. These findings imply that cargo receptors are essential for maintaining the architecture of ERGIC and Golgi by controlling COP I recruitment.
Mitrovic
Sandra
S
Biozentrum, University of Basel, CH-4056 Basel Switzerland.
Ben-Tekaya
Houchaima
H
Koegler
Eva
E
Gruenberg
Jean
J
Hauri
Hans-Peter
HP
D020126:Brefeldin A / Q000494:pharmacology; D022181:COP-Coated Vesicles / Q000187:drug effects / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D020868:Gene Silencing / Q000187:drug effects; D006056:Golgi Apparatus / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D006367:HeLa Cells; D006801:Humans; D037241:Mannose-Binding Lectins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D008954:Models, Biological; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects
C084004:LMAN1 protein, human; D037241:Mannose-Binding Lectins; D008565:Membrane Proteins; C094364:SURF4 protein, human; D020126:Brefeldin A