Component of the ERMES/MDM complex, which serves as a molecular tether to connect the endoplasmic reticulum and mitochondria. Components of this complex are involved in the control of mitochondrial shape and protein biogenesis and may function in phospholipid exchange. mdm10 is involved in the late assembly steps of the general translocase of the mitochondrial outer membrane (TOM complex). Functions in the tom40-specific route of the assembly of outer membrane beta-barrel proteins, including the association of tom40 with the receptor tom22 and small TOM proteins. Can associate with the SAM(core) complex as well as the mdm12-mmm-1 complex, both involved in late steps of the major beta-barrel assembly pathway, that is responsible for biogenesis of all outer membrane beta-barrel proteins. May act as a switch that shuttles between both complexes and channels precursor proteins into the tom40-specific pathway. Plays a role in mitochondrial morphology and in the inheritance of mitochondria. Component of the ER-mitochondria encounter structure (ERMES) or MDM complex, composed of mmm-1, mdm10, mdm12 and mdm34. Associates with the mitochondrial outer membrane sorting assembly machinery SAM(core) complex. The ERMES/MDM complex localizes to a few discrete foci (around 10 per single cell), that represent mitochondria-endoplasmic reticulum junctions. These foci are often found next to mtDNA nucleoids. Lacks alpha-helical transmembrane segments, suggesting that it resides in the membrane via beta-sheet conformations similar to those predicted for other outer membrane proteins and porin. Belongs to the MDM10 family.