Fam20C regulates protein secretion by Cab45 phosphorylation

J Cell Biol. 2020 Jun 1;219(6):e201910089. doi: 10.1083/jcb.201910089.

Abstract

The TGN is a key compartment for the sorting and secretion of newly synthesized proteins. At the TGN, soluble proteins are sorted based on the instructions carried in their oligosaccharide backbones or by a Ca2+-mediated process that involves the cargo-sorting protein Cab45. Here, we show that Cab45 is phosphorylated by the Golgi-specific protein kinase Fam20C. Mimicking of phosphorylation translocates Cab45 into TGN-derived vesicles, which goes along with an increased export of LyzC, a Cab45 client. Our findings demonstrate that Fam20C plays a key role in the export of Cab45 clients by fine-tuning Cab45 oligomerization and thus impacts Cab45 retention in the TGN.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • CRISPR-Cas Systems
  • Calcium-Binding Proteins / genetics
  • Calcium-Binding Proteins / metabolism*
  • Casein Kinase I / deficiency
  • Casein Kinase I / genetics
  • Casein Kinase I / metabolism*
  • Cell Line, Tumor
  • Extracellular Matrix Proteins / deficiency
  • Extracellular Matrix Proteins / genetics
  • Extracellular Matrix Proteins / metabolism*
  • Gene Knockout Techniques
  • Glycoproteins / genetics
  • Glycoproteins / metabolism*
  • Humans
  • Isoantigens / metabolism
  • Mutation
  • Phosphorylation
  • Protein Transport / genetics*
  • Protein Transport / physiology
  • RNA, Small Interfering
  • Recombinant Proteins
  • Seminal Plasma Proteins / metabolism
  • trans-Golgi Network / metabolism*

Substances

  • Calcium-Binding Proteins
  • Extracellular Matrix Proteins
  • Glycoproteins
  • Isoantigens
  • RNA, Small Interfering
  • Recombinant Proteins
  • SPACA3 protein, human
  • Seminal Plasma Proteins
  • SDF4 protein, human
  • Casein Kinase I
  • FAM20C protein, human