title: Characterization of p43(ARF), a derivative of the p43 component of multiaminoacyl-tRNA synthetase complex released during apoptosis.
abstract: In human, nine aminoacyl tRNA synthetases are associated with the three auxiliary proteins, p18, p38, and p43, to form a stable multiprotein complex. The p43 component, which has a potent tRNA binding capacity, is associated to the complex via its N-terminal moiety. This protein is also the precursor of the endothelial monocyte-activating polypeptide II (p43(EMAPII), corresponding to the C-terminal moiety of p43), a cytokine generated during apoptosis. Here we examined the cellular pathway that, starting from the p43 subunit of the complex, leads to this extracellular cytokine. We identified a new intermediate in this pathway, named p43(ARF) for Apoptosis-released Factor. This intermediate is produced in cellulo by proteolytic cleavage of endogenous p43 and is rapidly recovered in the culture medium. This p43 derivative was purified from the medium of human U937 cells subjected to serum starvation. It contains 40 additional N-terminal amino acid residues as compared with the cytokine p43(EMAPII) and may be generated by a member of the matrix metalloproteinase family. Recombinant p43(ARF) is a monomer in solution and binds tRNA with a Kd of approximately 6 nM, 30-fold lower than that of p43. Highly purified p43(ARF) or p43(EMAPII) do not stimulate the expression of E-selectin by human umbilical vein endothelial cells. Our results suggest that the cleavage of p43 and its cellular delocalization, and thus the release of this tRNA binding subunit from the complex, is one of the molecular mechanisms leading to the shut down of protein synthesis in apoptosis.
authors.affiliation: Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, 1 Avenue de la Terrasse, 91190 Gif-sur-Yvette, France.
authors.forename: Vyacheslav
authors.initials: V
authors.lastname: Shalak
authors.forename: Ludovic
authors.initials: L
authors.lastname: Guigou
authors.forename: Monika
authors.initials: M
authors.lastname: Kaminska
authors.forename: Marie-Paule
authors.initials: MP
authors.lastname: Wautier
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Wautier
authors.forename: Marc
authors.initials: M
authors.lastname: Mirande
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017209:Apoptosis / Q000187:drug effects; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D019040:E-Selectin / Q000378:metabolism; D004950:Esterases / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D051379:Mice; D024101:Mitochondrial Proteins; D010444:Peptide Elongation Factor Tu / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding; D012996:Solutions
chemical_list: D000951:Antigens, Neoplasm; D016895:Culture Media, Serum-Free; D019040:E-Selectin; D007377:Interleukin-3; D024101:Mitochondrial Proteins; D012996:Solutions; C091648:TUFM protein, human; D004950:Esterases; D010444:Peptide Elongation Factor Tu; D000604:Amino Acyl-tRNA Synthetases