Fig. 1.

Interactions between p105 and FIH. (A) Interaction of [³⁵S]methionine-labeled p105 polypeptides with extract from control cells (−) or cells induced with doxycycline (DOX) to express FLAG-FIH (+). Anti-FLAG immunoprecipitations; coprecipitating products are visualized by autoradiography. Residues 650–684 are essential for FIH interaction. (B) Alignment of residues 667–690 (fourth ankyrin repeat) of p105 with the ARD of FEM1β and UACA as well as the HIF-1α hydroxylation site (∗). (C) Interaction between FIH and transfected full-length PK-tagged p105, Asn-678 mutant p105 (N678A), in 293T cells exposed to DMOG (+) or vehicle control (−). EV, empty vector control. Anti-PK immunoprecipitates; coprecipitating FIH is detected by anti-FIH mAb. (D) Coimmunoprecipitation of endogenous FIH with p105 from HeLa cell extract. p105 IP, antibody to the C terminus of p105; CON IP, preimmune serum.