Component of the MRN complex, which plays a central role in double-strand break (DSB) repair, DNA recombination, maintenance of telomere integrity and meiosis. The complex possesses single-strand endonuclease activity and double-strand-specific 3'-5' exonuclease activity, which are provided by MRE11. RAD50 may be required to bind DNA ends and hold them in close proximity. This could facilitate searches for short or long regions of sequence homology in the recombining DNA templates, and may also stimulate the activity of DNA ligases and/or restrict the nuclease activity of MRE11 to prevent nucleolytic degradation past a given point (PubMed:11741547, PubMed:9590181, PubMed:9705271, PubMed:9651580). The complex may also be required for DNA damage signaling via activation of the ATM kinase (PubMed:15064416). In telomeres the MRN complex may modulate t-loop formation (PubMed:10888888). Binds 1 zinc ion per homodimer. Component of the MRN complex composed of two heterodimers RAD50/MRE11 associated with a single NBN (PubMed:8756642, PubMed:9590181, PubMed:9705271, PubMed:10839544, PubMed:26215093). As part of the MRN complex, interacts with MCM8 and MCM9; the interaction recruits the complex to DNA repair sites (PubMed:26215093). Component of the BASC complex, at least composed of BRCA1, MSH2, MSH6, MLH1, ATM, BLM, RAD50, MRE11 and NBN (PubMed:10783165). Found in a complex with TERF2 (PubMed:10888888). Interacts with RINT1 (PubMed:11096100). Interacts with BRCA1 via its N-terminal domain (PubMed:10426999). Interacts with DCLRE1C/Artemis (PubMed:15456891, PubMed:15723659). Interacts with MRNIP (PubMed:27568553). Interacts with CYREN (via XLF motif) (By similarity). (Microbial infection) Interacts with herpes simplex virus 1 protein UL12 (PubMed:20943970). Localizes to discrete nuclear foci after treatment with genotoxic agents. Expressed at very low level in most tissues, except in testis where it is expressed at higher level. Expressed in fibroblasts. The zinc-hook, which separates the large intramolecular coiled coil regions, contains 2 Cys residues that coordinate one molecule of zinc with the help of the 2 Cys residues of the zinc-hook of another RAD50 molecule, thereby forming a V-shaped homodimer. The two heads of the homodimer, which constitute the ATP-binding domain, interact with the MRE11 homodimer (By similarity). The disease is caused by variants affecting the gene represented in this entry. In case of infection by adenovirus E4, the MRN complex is inactivated and degraded by viral oncoproteins, thereby preventing concatenation of viral genomes in infected cells. Belongs to the SMC family. RAD50 subfamily. Contaminating sequence. Potential poly-A sequence.