Acts as receptor of the preprotein translocase complex of the outer mitochondrial membrane (TOM complex) (PubMed:12526792). Recognizes and mediates the translocation of mitochondrial preproteins from the cytosol into the mitochondria in a chaperone dependent manner (PubMed:12526792, PubMed:35025629). Mediates TBK1 and IRF3 activation induced by MAVS in response to Sendai virus infection and promotes host antiviral responses during virus infection (PubMed:20628368, PubMed:25609812, PubMed:32728199). Upon Sendai virus infection, recruits HSP90AA1:IRF3:BAX in mitochondrion and the complex induces apoptosis (PubMed:25609812). Forms part of the preprotein translocase complex of the outer mitochondrial membrane (TOM complex) which consists of at least 7 different proteins (TOMM5, TOMM6, TOMM7, TOMM20, TOMM22, TOMM40 and TOMM70) (PubMed:18331822). Interacts with CAPN8 (By similarity). Interacts with TRADD, TRAF6 and STING (PubMed:20628368). Interacts with MAVS; the interaction is enhanced by Sendai virus infection (PubMed:20628368). Interacts with HSPA8 and HSP90AA1; both interactions are required for preprotein mitochondrial import (PubMed:12526792). The interaction with HSP90AA1 is direct and mediates the association of TOMM70 with IRF3 and TBK1 (PubMed:20628368, PubMed:25609812). (Microbial infection) Interacts (via C-terminus) with SARS coronaviru/SARS-CoV and SARS coronavirus-2/SARS-CoV-2 virus protein ORF9b. (Microbial infection) Interacts with parasite T.gondii RH strain MAF1b1; the interaction impairs TOMM70 import activity, enables the parasite to associate with the host mitochondria and facilitates the association of MAF1b1 with MIB complex component SAMM50, promoting the formation of SPOTs (structures positive for outer mitochondrial membrane (OMM)); the interaction is probably indirect. (Microbial infection) During parasite T.gondii-mediated infection, enriched at the interface between the host mitochondria and the parasitopharous vacuole. Belongs to the Tom70 family. Extended N-terminus.