RRC ID 59405
Author Saegusa K, Sato M, Morooka N, Hara T, Sato K.
Title SFT-4/Surf4 control ER export of soluble cargo proteins and participate in ER exit site organization.
Journal J Cell Biol
Abstract Lipoproteins regulate the overall lipid homeostasis in animals. However, the molecular mechanisms underlying lipoprotein trafficking remain poorly understood. Here, we show that SFT-4, a Caenorhabditis elegans homologue of the yeast Erv29p, is essential for the endoplasmic reticulum (ER) export of the yolk protein VIT-2, which is synthesized as a lipoprotein complex. SFT-4 loss strongly inhibits the ER exit of yolk proteins and certain soluble cargo proteins in intestinal cells. SFT-4 predominantly localizes at ER exit sites (ERES) and physically interacts with VIT-2 in vivo, which suggests that SFT-4 promotes the ER export of soluble proteins as a cargo receptor. Notably, Surf4, a mammalian SFT-4 homologue, physically interacts with apolipoprotein B, a very-low-density lipoprotein core protein, and its loss causes ER accumulation of apolipoprotein B in human hepatic HepG2 cells. Interestingly, loss of SFT-4 and Surf4 reduced the number of COPII-positive ERES. Thus, SFT-4 and Surf4 regulate the export of soluble proteins, including lipoproteins, from the ER and participate in ERES organization in animals.
Volume 217(6)
Pages 2073-2085
Published 2018-6-4
DOI 10.1083/jcb.201708115
PII jcb.201708115
PMID 29643117
PMC PMC5987718
MeSH Animals Caenorhabditis elegans / metabolism* Caenorhabditis elegans / ultrastructure Caenorhabditis elegans Proteins / metabolism* Egg Proteins / metabolism Endoplasmic Reticulum / metabolism* Endoplasmic Reticulum / ultrastructure Hep G2 Cells Humans Intestines / ultrastructure Membrane Proteins / metabolism* Protein Binding Protein Transport RNA Interference Solubility
IF 8.891
Times Cited 9