Fig. 2

The TMD and the cytosolic KKEV motif of Cisd2 jointly ensure its efficient localization in the early secretory pathway. a Schematic representation of CD1b-Cisd2 fusion proteins. Various portions of the Cisd2 protein were fused with the CD1b extracellular domain and TMD. In some constructs, the C-terminal KKEV motif was mutated either by replacing three lysine residues with serine residues, or by adding four serine residues at the C-terminal extremity. The detailed amino acid sequence of these proteins is shown in Additional file 6. b Colocalization of CD1b-Cisd2 fusion proteins with an ER marker. HEK cells co-expressing the indicated CD1b-Cisd2 chimera and ER-YFP were labeled by immunofluorescence, using an anti-CD1b antibody. CD1b-M1, 2 and 3 were largely localized in the ER, CD1b-M4 and 5 were not. c. Colocalization of CD1b-Cisd2 fusion proteins with the Golgi apparatus. HEK cells expressing the indicated proteins were labeled by immunofluorescence, using an anti-CD1b antibody. The Golgi complex was revealed with an anti-giantin antibody. All pictures were taken with a confocal microscope (LSM700, Zeiss). Scale bar: 10 μm. The asterisks indicate a nucleus with a discontinuous staining of the nuclear envelope, the arrows point to a Golgi apparatus. A second panel of pictures is shown in Additional file 7