EhP3, a homolog of 14-3-3 family of protein participates in actin reorganization and phagocytosis in Entamoeba histolytica

PLoS Pathog. 2019 May 16;15(5):e1007789. doi: 10.1371/journal.ppat.1007789. eCollection 2019 May.

Abstract

The highly conserved proteins of the 14-3-3 family are universal adaptors known to regulate an enormous range of cellular processes in eukaryotes. However, their biological functions remain largely uncharacterized in pathogenic protists comprising of several 14-3-3 protein isoforms. In this study, we report the role of 14-3-3 in coordinating cytoskeletal dynamics during phagocytosis in a professional phagocytic protist Entamoeba histolytica, the etiological agent of human amebiasis. There are three isoforms of 14-3-3 protein in amoeba and here we have investigated Eh14-3-3 Protein 3 (EhP3). Live and fixed cell imaging studies revealed the presence of this protein throughout the parasite phagocytosis process, with high rate of accumulation at the phagocytic cups and closed phagosomes. Conditional suppression of EhP3 expression caused significant defects in phagocytosis accompanied by extensive diminution of F-actin at the site of cup formation. Downregulated cells also exhibited defective recruitment of an F-actin stabilizing protein, EhCoactosin at the phagocytic cups. In addition, mass spectrometry based analysis further revealed a large group of EhP3-associated proteins, many of these proteins are known to regulate cytoskeletal architecture in E histolytica. The dynamics of these proteins may also be controlled by EhP3. Taken together, our findings strongly suggest that EhP3 is a novel and a key regulatory element of actin dynamics and phagocytosis in E. histolytica.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 14-3-3 Proteins / genetics
  • 14-3-3 Proteins / metabolism*
  • Actins / metabolism*
  • Amino Acid Sequence
  • Animals
  • Cytoskeleton / metabolism*
  • Entamoeba histolytica / physiology
  • Entamoebiasis / metabolism
  • Entamoebiasis / parasitology*
  • Erythrocytes / metabolism
  • Erythrocytes / parasitology*
  • Female
  • Humans
  • Immunization
  • Mice
  • Mice, Inbred BALB C
  • Phagocytosis*
  • Phylogeny
  • Protozoan Proteins / genetics
  • Protozoan Proteins / metabolism*
  • Sequence Homology

Substances

  • 14-3-3 Proteins
  • Actins
  • Protozoan Proteins

Grants and funding

We acknowledge Central Instrument Facility, School of Life Sciences, JNU, Advanced Instrument Research Facility, JNU for microscopy and SPR studies. SA thanks the Department of Science and Technology for DST Inspire Faculty Award and Grant. AB thanks the Department of Science and Technology for JC Bose Fellowship and the Department of Biotechnology for SERB grant. PPR thanks the Council of Scientific and Industrial Research (CSIR) for SRF Fellowship. We also thank the FIST and PURSE grant of School of Life Sciences, JNU. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.