Chaperone protein which plays an important role in mitochondrial iron-sulfur cluster (ISC) biogenesis (PubMed:26702583). Interacts with and stabilizes ISC cluster assembly proteins FXN, NFU1, NFS1 and ISCU (By similarity). Regulates erythropoiesis via stabilization of ISC assembly (PubMed:21123823). May play a role in the control of cell proliferation and cellular aging (PubMed:8454632). Interacts strongly with the intermediate form of FXN and weakly with its mature form. Interacts with HSCB. Associates with the mitochondrial contact site and cristae organizing system (MICOS) complex, composed of at least MICOS10/MIC10, CHCHD3/MIC19, CHCHD6/MIC25, APOOL/MIC27, IMMT/MIC60, APOO/MIC23/MIC26 and QIL1/MIC13. This complex was also known under the names MINOS or MitOS complex. The MICOS complex associates with mitochondrial outer membrane proteins SAMM50, MTX1, MTX2 and DNAJC11, mitochondrial inner membrane protein TMEM11 and with HSPA9. Interacts with DNLZ, the interaction is required to prevent self-aggregation. Interacts with TESPA1. Interacts with PDPN. Interacts with NFU1, NFS1 and ISCU. Found in all the cell types examined. Not induced by heat shock, instead protein level is decreased. Two forms of the protein have been found, MOT-1, found in mortal cells and MOT-2, found in immortal cells. The sequence of MOT-2 is shown here. Belongs to the heat shock protein 70 family.