FIG. 9.

Two-hybrid interaction analysis between N- and C-terminal MTK1 segments. (A) Sets of ACT-MTK1 N-terminal constructs and DB-MTK1 C-terminal constructs, as shown schematically by horizontal bars and numerically in the table, were transformed into L40 tester cells. The presence and absence of the N-C interaction, as deduced from growth on histidine-deficient plates and β-Gal expression, are indicated by plus and minus signs, respectively. The GADD45 binding site (gray), kinase catalytic domain (black), and four regions (A1, A2, B1, and B2) are also indicated. (B) Some, but not all, constitutively active MTK1 mutants are defective in the N-C interaction, as detected by two-hybrid analysis. The ACT-MTK1-N construct contains the MTK1(22-1103) segment, and the DB-MTK1-C construct contains the MTK1(1104-1607) segment. Either a wild-type (wt) or a mutant sequence, as indicated in the figure, was tested in each pair. A minus sign indicates the corresponding vector (pACTII or pBTM118) without an insert. +His, with histidine; −His, without histidine.