Extended Data Fig. 9: Analysis of the extra subunit of GPIT complex.
From: Structure of human glycosylphosphatidylinositol transamidase
a, Cryo-EM map of the GPIT complex with six additional transmembrane helices, viewed in parallel to the membrane plane. Subunits PIGK, GPAA1, PIGU, PIGS, and PIGT are colored in cyan, blue, purple, pink, and red, respectively. The extra helices are colored in grey. b, Mass-spectrometry analysis of the purified GPIT protein sample. Subunits of GPIT complexes are highlighted in green. The putative extra subunit RNF121 is highlighted in red. c, Manually-built poly-alanine model of the extra subunit, overlaid with corresponding cryo-EM map (left). 3D structure of the RNF121 predicted by AlphaFold2 (middle); superimposition of structures of extra subunit and RNF121 (right). d, Top-down view of the transmembrane domain of the GPIT-RNF121 complex. e, Western blot analysis of strep tag purified samples (co-expressed GPIT-RNF121 or RNF121 alone) using antibodies against His tag and strep tag to monitor RNF121 and PIGU, respectively. The letters S and E represent supernatant of detergent solubilized cell membrane and elution sample from streptavidin beads, respectively. The experiments were repeated independently 3 times with similar results.
