Figure 4.

A central region of TOR1 is required for toxicity of TOR1 deletion derivatives. (A) Diagram of TOR1 internal deletions with the FRB and kinase domains depicted by boxes. The D2275A kinase-inactive mutation is represented by a star. The specific amino acids (AA) deleted in each mutant, the ability to inhibit growth when overexpressed, and the ability to complement and restore growth at 39°C in a synthetic lethal tor1 Δsrk1 mutant strain (CAY7) are indicated. (B) TOR1 deletion mutants were expressed in the Δtor1 strain CAY6, and ability to inhibit growth on galactose medium was assessed. Cells were grown on glucose or galactose medium lacking tryptophan for 96 h at 30°C. DA indicates the D2275A kinase-active site mutation. The numbers on the plate designation correspond to the construct number indicated to the left in panel A. (C) TOR1 deletion mutant proteins were expressed in the Δtor1 strain CAY6 and detected by Western blot with α-HA antibody. Numbers above the Western blot correspond to the construct numbers listed to the left in panel A. Numbers at the left indicate molecular mass in kilodaltons.