Interaction of the tobacco lectin with histone proteins
Schouppe, Dieter × Ghesquière, Bart Menschaert, Gerben De Vos, Winnok Bourque, Stéphane Trooskens, Geert Proost, Paul Gevaert, Kris Van Damme, Els J M #
American Society of Plant Biologists
Plant Physiology vol:155 pages:1091-1102
The Nicotiana tabacum agglutinin or Nictaba is a member of a novel class of plant lectins residing in the nucleus and the cytoplasm of tobacco cells. Since tobacco lectin expression is only observed after the plant has been subjected to stress situations such as jasmonate treatment or insect attack, Nictaba is believed to act as a signaling protein involved in the stress physiology of the plant. In this paper a nuclear proteomics approach was followed to identify the binding partners for Nictaba in the nucleus and the cytoplasm of Nicotiana tabacum cv Xanthi cells. Using lectin affinity chromatography and pull down assays it was shown that Nictaba interacts primarily with histone proteins. Binding of Nictaba with histone H2B was confirmed in vitro using affinity chromatography of purified calf thymus histone proteins on a Nictaba column. Elution of Nictaba-interacting histone proteins was achieved with 1 M GlcNAc. Moreover, mass spectrometry analyses indicated that the Nictaba-interacting histone proteins are modified by O-GlcNAc. Since the lectin-histone interaction was shown to be carbohydrate dependent it is proposed that Nictaba might fulfill a signaling role in response to stress, by interacting with O-GlcNAcylated proteins in the plant cell nucleus.