Identification and characterization of proteins interacting with plant formins

Formins are evolutionarily conserved proteins participating in actin and microtubule organisation, affecting thus also intracellular transport, cell growth, morphogenesis and cell polarity. All formins contain FH2 domain, known to dimerize and act as a nucleator of actin. Angiosperms have two formin clades, Class I and Class II, which are distinguished by domain organisation. Based on knowledge from animal models and protein sequence homology, two groups of candidate membrane-associated formin interactors have been proposed in Arabidopsis (Cvrčková, 2013). First group of candidates consists of FYVE domain-containing proteins FAB1A (At4g33240) and FAB1B (At3g14270), the other contains proteins with BAR and SH3 domains AtSH3P1 (At1g31440), AtSH3P2 (At4g346600) and AtSH3P3 (At4g18060). Yeast two hybrid assay was used to examine protein interactions of selected proteins from both candidate groups (FAB1A, SH3P2 and SH3P3) with FH2 domains representing both plant formin clades. The same experimental setup was also used to test dimerization among FH2 domains of plant formins. Translational fusions of FH2 domains from Class I formins AtFH1 (At3g25500), AtFH5 (At5g54650) and Class II representatives AtFH13 (At5g58160) and AtFH14 (At1g31810) with the GAL4 activation domain have been co-expressed in yeast with GAL4..