Interactions between AKINβγ/βγI and the AKINα1 and α2 kinases by two-hybrid experiments and in vitro binding assays. A, Qualitative β-galactosidase enzyme assays were performed between full-length AKINβγ/βγI or AKINβγ CBS4 domain and AKINα1 and α2 kinases. B, In vitro binding assays. Due to their similar molecular masses, AKINβγ and AKINα2 proteins were synthesized by in vitro transcription/translation system (Promega) without or with (*) 35S-Met labeling and incubated alone or by pairs, respectively. After coimmunoprecipitation with HA or c-Myc antibodies, proteins were separated by 10% SDS-PAGE and exposed to an x-ray film.