biostudies-literatureGuna AHoward Hughes Medical InstituteNHGRI NIH HHSNINDS NIH HHS317-322https://www.ebi.ac.uk/biostudies/studies/S-EPMC9674023biostudies-literatureUnknown378(6617)In the mitochondrial outer membrane, α-helical transmembrane proteins play critical roles in cytoplasmic-mitochondrial communication. Using genome-wide CRISPR screens, we identified mitochondrial carrier homolog 2 (MTCH2), and its paralog MTCH1, and showed that it is required for insertion of biophysically diverse tail-anchored (TA), signal-anchored, and multipass proteins, but not outer membrane β-barrel proteins. Purified MTCH2 was sufficient to mediate insertion into reconstituted proteoliposomes. Functional and mutational studies suggested that MTCH2 has evolved from a solute carrier transporter. MTCH2 uses membrane-embedded hydrophilic residues to function as a gatekeeper for the outer membrane, controlling mislocalization of TAs into the endoplasmic reticulum and modulating the sensiScience (New York, N.Y.)MTCH2 is a mitochondrial outer membrane protein insertase.PMC9674023F31 NS115380RM1 HG009490Shaffer KCLReplogle JMMuthukumar GJones JJWeissman JSChou TFGuna AStevens TAPogson ANEsantsi TKVoorhees RMLomenick BInglis AJWang MLfalseMTCH2 is a mitochondrial outer membrane protein insertase.In the mitochondrial outer membrane, α-helical transmembrane proteins play critical roles in cytoplasmic-mitochondrial communication. Using genome-wide CRISPR screens, we identified mitochondrial carrier homolog 2 (MTCH2), and its paralog MTCH1, and showed that it is required for insertion of biophysically diverse tail-anchored (TA), signal-anchored, and multipass proteins, but not outer membrane β-barrel proteins. Purified MTCH2 was sufficient to mediate insertion into reconstituted proteoliposomes. Functional and mutational studies suggested that MTCH2 has evolved from a solute carrier transporter. MTCH2 uses membrane-embedded hydrophilic residues to function as a gatekeeper for the outer membrane, controlling mislocalization of TAs into the endoplasmic reticulum and modulating the sensi2022-01-01T00:00:00Z2022 Oct2025-04-25T21:04:44.54Z2025-04-06T08:35:08.465ZS-EPMC96740233626479710.1126/science.add1856