In Vitro Binding of ARC1 to the SRK kinase domains. (A) The GSTARC1 (C-terminal) fusion protein was mixed with various resin-bound MBP fusion proteins. The presence of the GSTARC1 (C-terminal) fusion protein was detected by using a GST Western blotting kit. Lane 1, 5 μl of the GST positive control provided with the GST Western blotting kit; lanes 2–8, in vitro binding assays. (B) Coomassie blue-stained gel of the in vitro binding assays. Lane M, marker lane; lane 1, 5 μl of the GST positive control provided with the GST Western blotting kit; lanes 2–8, the various MBP fusion proteins in the in vitro binding assays. For the MBP fusion proteins, the top band in each lane represents the full-length fusion protein. The bands below represent degradation products.