Non-proteolytic activation of cellular protransglutaminase (placenta macrophage Factor XIII)

J. Polgar, V. Hidasi, L. Muszbek

Research output: Contribution to journalArticle

67 Citations (Scopus)

Abstract

Plasma Factor XIII is a zymogen (plasma protransglutaminase) with the tetrameric structure A2B2, whereas the cellular protransglutaminase, i.e. Factor XIII in the platelet and monocyte/macrophage, consists exclusively of A subunits (A2). It is generally accepted that at Ca2+ concentrations comparable with that in plasma the proteolytic removal of an N-terminal activation peptide is the prerequisite for the Ca2+-induced formation of a catalytically active configuration of subunit A. In this study it was demonstrated that at high concentrations NaCl or KCl induced a non-proteolytic activation of cellular (placental macrophage) but not plasma protransglutaminase. The activation depended on time and salt concentration, and Ca2+, in the range 0-20 mM, greatly enhanced the activation process. At 1.25 M-NaCl maximal activation occurred within 60 min in the presence of 2mM-CaCl2, and even at physiological NaCl concentration a slow progressive activation could be observed in the presence of Ca2+. The specific activity of salt-activated Factor XIII was 1.5-2.0-fold higher than that obtained after thrombin activation. The non-proteolytic activation of cellular protransglutaminase was abolished by the addition of subunit B of plasma Factor XIII in stoichiometric amount, which suggests that (one of) the physiological function(s) of the B subunit in plasma Factor XIII is to prevent the slow spontaneous activation of A subunit that would occur in a plasmatic environment.

Original languageEnglish
Pages (from-to)557-560
Number of pages4
JournalBiochemical Journal
Volume267
Issue number2
DOIs
Publication statusPublished - 1990

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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