Fig. 6. XKLC4 interacts with domain III of GBP. (A) Schematic diagram of GBP deletion constructs. The wild-type (WT) protein is shown on top, with the conserved domains represented as boxes, and numbers indicating the first and last amino acid residues of the domains. For the deletion constructs, the numbers indicate the residues that flank the deletions. (B,C) Association of XKLC4 with GBP deletion mutants in vivo. (B) Xenopus embryos were injected at the 2-4-cell stage with XKLC4-HA RNA and WT GBP-myc, N-I-myc, -II-myc or C-III-myc RNA as indicated above each lane. After a 4-5-hour incubation, lysates were immunoprecipitated (IP) with anti-HA antibody or no antibody (no Ab) as a negative control. A portion of each sample was taken prior to immunoprecipitation (IP) to show expression of injected RNAs (total lysates, right panel). Samples were immunoblotted with anti-HA and anti-myc antibodies (Blot). (C) As in B, embryos were injected with XKLC4-HA RNA and WT GBP-myc, C-I-myc, N-III-myc or C-III-myc RNA, as indicated above each lane. Samples were processed and immunoblotted as in B. A portion of each sample was taken prior to immunoprecipitation to show expression of injected RNAs (total lysates, right panel). (D) Binding of XKLC4 and GSK3 to GBP in vivo is mutually exclusive. Xenopus embryos were injected at the 2-4-cell stage with XKLC4-HA RNA, WT GBP-myc RNA and WT GSK3-myc or kinase-dead (kd) GSK3-myc RNA as indicated above each lane. After a 4-5-hour incubation, lysates were immunoprecipitated with anti-HA antibody or no antibody (no Ab) as a negative control (left panel). A portion of each sample was taken prior to immunoprecipitation to show expression of injected RNAs (total lysates, right panel). Samples were immunoblotted with anti-HA and anti-myc antibodies (Blot).