Figure 1.

Bnip3 interacts with Opa1. (A) HeLa cells were co-transfected with plasmids for Opa1 and HA–Bnip3, or (B) HA–Bnip3 mutants, as indicated. (C) Endogenous interactions were observed in HeLa cells exposed (+) or not (−) to hypoxia to induce Bnip3 expression. Immunoprecipitations (IPs) were performed on crosslinked mitochondria (mito input, 1/20 of IP) using anti-Opa1, anti-HA or no antibodies (−), and analysed by western blots using the indicated antibodies. Migration of molecular weight markers is shown on the right. The batch of affinity media used in (C) released a major contaminant (indicated by the asterisk), probably immunoglobulin light chains (MW∼25 kDa). Note in (C) that low basal levels of endogenous Bnip3 expressed under normoxia (IP Opa1, hypoxia−) are associated with Opa1. HA, haemagglutinin; HA–Bnip3, haemagglutinin-tagged Bnip3.