Phg1p is a nine-transmembrane protein superfamily member involved in dictyostelium adhesion and phagocytosis

J Biol Chem. 2000 Nov 3;275(44):34287-92. doi: 10.1074/jbc.M006725200.


To identify the molecular mechanisms involved in phagocytosis, we generated random insertion mutants of Dictyostelium discoideum and selected two mutants defective for phagocytosis. Both represented insertions in the same gene, named PHG1. This gene encodes a polytopic membrane protein with an N-terminal lumenal domain and nine potential transmembrane segments. Homologous genes can be identified in many species; however, their function is yet to be elucidated. Disruption of PHG1 caused a selective defect in phagocytosis of latex beads and Escherichia coli, but not Klebsiella aerogenes bacteria. This defect in phagocytosis was caused by a decrease in the adhesion of mutant cells to phagocytosed particles. These results indicate that the Phg1 protein is involved in the adhesion of Dictyostelium to various substrates, a crucial event of phagocytosis and demonstrate the usefulness of a genetic approach to dissect the molecular events involved in the phagocytic process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Adhesion / physiology*
  • DNA, Protozoan
  • Dictyostelium / genetics
  • Dictyostelium / physiology*
  • Dictyostelium / ultrastructure
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / physiology*
  • Microscopy, Electron, Scanning
  • Molecular Sequence Data
  • Mutation
  • Phagocytosis / physiology*
  • Phenotype
  • Sequence Homology, Amino Acid


  • DNA, Protozoan
  • Membrane Proteins
  • Phg1 protein, Dictyostelium discoideum