Madm interacts biochemically with BunA. (a) Western blot showing that endogenous BunA is pulled down together with HA-Madm. Anti-HA beads were used to capture either HA-Madm or HA-eGFP as a negative control, respectively. A tenth of the cell lysate was used for the input control. (b, c) Co-localization studies of BunA and Madm in Drosophila S2 cells. In (b-b") a stable cell line capable of producing GFP-BunA in every cell was transiently transfected with a plasmid leading to expression of HA-Madm in a subset of cells (and vice versa in c-c"). Co-overexpression of GFP-BunA influences the localization of HA-Madm, resulting in a less dispersed pattern (c-c"). (d) GFP-BunA co-localizes with the Golgi marker GMAP210 (Golgi microtubule-associated protein of 210 kDa) . (e, f) Schematic drawing of BunA (e) and Madm (f) constructs tested in Y2H and co-IP assays for an interaction with full-length Madm and BunA, respectively. The results of the Y2H and co-IP experiments are summarized on the left [see Additional files 2 and 3 for the primary results]. The physical interaction of BunA and Madm is mediated by a short protein sequence encompassing the conserved motif 2 in BunA and a carboxy-terminal sequence in Madm, respectively [see Additional file 4 for alignments].