Characterization of the biochemical and biophysical properties of the phosphatidylserine receptor (PS-R) gene product

Nitu Tibrewal, Tong Liu, Hong Li, Raymond B. Birge

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29 Scopus citations


The PS-R gene product was originally described as a cell surface receptor that interacts with externalized phosphatidylserine (PS) on apoptotic cells, but more recent studies have shown that it plays a critical role in organ development and terminal differentiation of many cell types during embryogenesis. Despite these important developmental functions, the biochemical and molecular properties of PS-R are poorly understood. Here we have used several approaches to show that PS-R undergoes processive post-translational protein cross-linking to form covalent multimers within the nuclear compartment. Although PS-R has a potential Glu-Glu (QQ) duet that is often targeted by transglutaminase TG-2, the oligomerization of PS-R was not effected by QQ-AA mutation, or when PS-R gene product was expressed in TG-2 (-/-) fibroblasts. Pulse-chase experiments with 35S-methionine indicates that the PS-R undergoes an initial proteolytic cleavage, followed by progressive multimerization of the monomeric subunits over time. In summary, we report here that PS-R is modified by an unusual post-translational modification, and we speculate that homomultimer of PS-R might be playing an important function as a scaffolding protein in the nucleus.

Original languageEnglish (US)
Pages (from-to)119-125
Number of pages7
JournalMolecular and Cellular Biochemistry
Issue number1-2
StatePublished - Oct 2007

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Clinical Biochemistry
  • Cell Biology


  • Apoptotic cells
  • Phagocytosis
  • Phosphatidylserine
  • Post Translational Modification
  • Protein Cross Linking


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