GOPC facilitates the sorting of syndecan-1 in polarized epithelial cells

Mol Biol Cell. 2022 Sep 1;33(10):ar86. doi: 10.1091/mbc.E22-05-0165. Epub 2022 Jul 13.

Abstract

The trans-Golgi network must coordinate sorting and secretion of proteins and lipids to intracellular organelles and the plasma membrane. During polarization of epithelial cells, changes in the lipidome and the expression and distribution of proteins contribute to the formation of apical and basolateral plasma membrane domains. Previous studies using HeLa cells show that the syndecan-1 transmembrane domain confers sorting within sphingomyelin-rich vesicles in a sphingomyelin secretion pathway. In polarized Madin-Darby canine kidney cells, we reveal differences in the sorting of syndecan-1, whereupon the correct trafficking of the protein is not dependent on its transmembrane domain and changes in sphingomyelin content of cells during polarization. Instead, we reveal that correct basolateral targeting of syndecan-1 requires a full-length PDZ motif in syndecan-1 and the PDZ domain golgin protein GOPC. Moreover, we reveal changes in Golgi morphology elicited by GOPC overexpression. These results suggest that the role of GOPC in sorting syndecan-1 is indirect and likely due to GOPC effects on Golgi organization.

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism*
  • Animals
  • Cell Membrane / metabolism
  • Cell Polarity
  • Dogs
  • Epithelial Cells / metabolism
  • Golgi Matrix Proteins / metabolism*
  • HeLa Cells
  • Humans
  • Madin Darby Canine Kidney Cells
  • Protein Transport
  • Sphingomyelins / metabolism
  • Syndecan-1* / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • GOPC protein, human
  • Golgi Matrix Proteins
  • Sphingomyelins
  • Syndecan-1