CACTIN is an essential nuclear protein in Arabidopsis and may be associated with the eukaryotic spliceosome

CACTIN is a conserved eukaryotic protein without known functional domains. Previous research revealed that CACTIN is essential in animals and protists and that it may function in inflammation pathways in animals; however, these pathways are not as broadly conserved as CACTIN. Therefore, the ancestral molecular function of CACTIN remains unknown. Our studies using Arabidopsis show that CACTIN is required for embryogenesis. Fluorescently tagged CACTIN localizes to nuclear speckles and colocalizes with known splicing proteins. In yeast-two-hybrid studies, we found that CACTIN binds to a putative component of the spliceosome. These findings support a possible role for CACTIN in splicing. Structured summary of protein interactions: Cactin and SR45colocalize by fluorescence microscopy (View interaction) Cactin and RSP31colocalize by fluorescence microscopy (View interaction) Cactin and AT5G63440physically interacts withby two hybrid (View Interaction: 1, 2, 3) Cactin and AT5G63440colocalize by fluorescence microscopy (View interaction) ATG7physically interacts with ATG12A by two hybrid (View Interaction: 1, 2) (C) 2013 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved.