Fig. 2. FAM83 proteins interact with CK1 isoforms.

A. Mass fingerprinting of protein interactors of FAM83A–H proteins tagged N-terminally (HEK 293 cells) or C-terminally (U2OS cells) with GFP (fig. S2, A and B) identified one or more CK1 isoforms. These tables show the values for the top 3 precursor ion intensities of the indicated CK1 isoforms pulled down with each GFP-FAM83 protein (A–H) expressed in HEK 293 cells and each FAM83-GFP protein (A–H) expressed in U2OS cells. GFP expressed in each cell line was a negative control. Scaffold Q/Q+S V4.4.6 was used for analysis of the LC-MS/MS data from HEK 293 cells, and scaffold V4.3 was used for analysis of the LC-MS-MS data from U2OS cells. FAM83B-GFP did not express in U2OS cells. B. GFP Immunoprecipitates (IP) of GFP control or GFP-FAM83A–H proteins expressed in HEK 293 cells were immunoblotted (IB) with antibodies recognizing the indicated CK1 isoforms and other proteins known to interact with FAM83 family proteins. Short Exp., short exposure; Long Exp., long exposure. C. Extracts of wild-type (WT) or GFP-FAM83B knockin (^GFP/GFPFAM83B) HaCaT cells were immunoprecipitated with GFP-TRAP A beads and immunoblotted to detect the indicated CK1 isoforms. GAPDH was used as a loading control. FT, flow through. D. As in C., except that proteins were immunoprecipitated from WT and FAM83G-GFP knockin (FAM83G^GFP/GFP) U2OS cell extracts. E. U2OS extracts were immunoprecipitated using either pre-immune IgG or an antibody recognizing CK1α coupled to Protein-G sepharose beads and immunoblotted with antibodies recognizing the indicated FAM83 proteins and GAPDH. All blots are representative of 3 independent experiments.