A model for Mcl1 regulation of Bak‐dependent MOMP A model for Mcl1 regulation of Bak‐dependent MOMP. As described in the text, Mcl1 and its binding partner Bak seem to have similarities to Bcl‐XL and its binding partner Bax, with the exception that Mcl1 and Bak are constitutively anchored to the outer mitochondrial membrane (OMM) by their respective transmembrane segments. A model for Mcl1 regulation of Bak‐dependent MOMP. As described in the text, Mcl1 and its binding partner Bak seem to have similarities to Bcl‐XL and its binding partner Bax, with the exception that Mcl1 and Bak are constitutively anchored to the outer mitochondrial membrane (OMM) by their respective transmembrane segments. Hybrid models involving Mcl1/Bax and Bcl‐XL/Bak are also relevant, as these interactions also exist. As in the Bcl‐XL model, antagonism of Mcl1 by a sensitizing BH3‐only protein (for example, Noxa) or by a chemical mimetic (such as, obatoclax or sabutoclax) can reinstate Bak‐driven MOMP. As in the Bcl‐XL model, the latter is probably seeded by Bak oligomers (pore progenitor) but requires additional membrane‐dependent events to construct pores capable of releasing the protein content of the mitochondrial intermembrane space, including apoptotic regulators such as cytochrome c and Smac. Bak, Bcl2 antagonist killer; Bcl‐XL, Bcl2‐like protein XL; BH3, Bcl2 homology domain 3; COO−, carboxyl; Mcl1, myeloid cell leukaemia 1; MOMP, mitochondrial outer membrane permeabilization; Smac, second mitochondrial activator of caspase. Franziska Ertel et al. EMBO Rep. 2013;14:328-336 © as stated in the article, figure or figure legend