Interaction of the C-terminal domain of p43 and the α subunit of ATP synthase: Its functional implication in endothelial cell proliferation

Sun Young Chang, Sang Gyu Park, Sunghoon Kim, Chang Yuil Kang

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62 Citations (Scopus)

Abstract

Human p43 is associated with macromolecular tRNA synthase complex and known as a precursor of endothelial monocyte-activating polypeptide II (EMAP II). Interestingly, p43 is also secreted to induce proinflammatory genes. Although p43 itself seems to be a cytokine working at physiological conditions, most of the functional studies have been obtained with its C-terminal equivalent, EMAP II. To gain an insight into the working mechanism of p43/EMAP II, we used EMAP II and searched for an interacting cell surface molecule. The level of EMAP II-binding molecule(s) was significantly increased in serum-starved tumor cells. Thus, the EMAP II-binding molecule was isolated from the membrane of the serum-starved CEM cell. The isolated protein was determined to be the a subunit of ATP synthase. The interaction of EMAP II and α-ATP synthase was confirmed by enzyme-linked immunosorbent assay and in vitro pull down assays and blocked with the antibodies raised against EMAP II and α-ATP synthase. The binding of EMAP II to the surface of serum-starved cells was inhibited in the presence of soluble α-ATP synthase. EMAP II inhibited the growth of endothelial cells, and this effect was relieved by soluble α-ATP synthase. Anti-α-ATP synthase antibody also showed an inhibitory effect on the proliferation of endothelial cells mimicking the activity of EMAP II. These results suggest the potential interaction of p43/EMAP II with α-ATP synthase and its role in the proliferation of endothelial cells.

Original languageEnglish
Pages (from-to)8388-8394
Number of pages7
JournalJournal of Biological Chemistry
Volume277
Issue number10
DOIs
Publication statusPublished - 2002 Mar 8

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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