Abstract
Mitochondrial cristae membranes are the oxidative phosphorylation sites in cells. Crista
junctions (CJs) form the highly curved neck regions of cristae and are thought to function as
selective entry gates into the cristae space. Little is known about how CJs are generated and
maintained. We show that the central coiled-coil domain of the mitochondrial contact and cristae
organizing system (MICOS) subunit Mic60 forms an elongated, bow tie-shaped tetrameric
assembly. Mic19 promotes Mic60 tetramerization via a conserved interface between the Mic60
mitofilin and Mic19 CHCH domains. Dimerization of mitofilin domains exposes a crescent-
shaped membrane-binding site with convex curvature tailored to interact with curved CJ necks.
Our study suggests that the Mic60-Mic19 subcomplex transverses CJs as a molecular strut, thereby
controlling CJ architecture and function