[Iron-sulfur cluster co-chaperone protein HscB, mitochondrial]: Acts as a co-chaperone in iron-sulfur cluster assembly in mitochondria (PubMed:20668094). Required for incorporation of iron- sulfur clusters into SDHB, the iron-sulfur protein subunit of succinate dehydrogenase that is involved in complex II of the mitochondrial electron transport chain (PubMed:26749241). Recruited to SDHB by interaction with SDHAF1 which first binds SDHB and then recruits the iron-sulfur transfer complex formed by HSC20, HSPA9 and ISCU through direct binding to HSC20 (PubMed:26749241). Plays an essential role in hematopoiesis (By similarity). {ECO:0000250|UniProtKB:Q8K3A0, ECO:0000269|PubMed:20668094, ECO:0000269|PubMed:26749241}. [Iron-sulfur cluster co-chaperone protein HscB, cytoplasmic]: Acts as a co-chaperone in iron-sulfur cluster assembly in the cytoplasm (PubMed:29309586). Also mediates complex formation between components of the cytosolic iron-sulfur biogenesis pathway and the CIA targeting complex composed of CIAO1, DIPK1B/FAM69B and MMS19 by binding directly to the scaffold protein ISCU and to CIAO1 (PubMed:29309586). This facilitates iron-sulfur cluster insertion into a number of cytoplasmic and nuclear proteins including POLD1, ELP3, DPYD and PPAT (PubMed:29309586). . This is the function of Ensembl gene identifier ENSG00000100209 (HSCB, HscB mitochondrial iron-sulfur cluster cochaperone).