SMC5
Description
The SMC5 (structural maintenance of chromosomes 5) is a protein-coding gene located on chromosome 9.
SMC5, also known as structural maintenance of chromosomes protein 5, is a protein encoded by the SMC5 gene in humans. This protein is a core component of the SMC5-SMC6 complex, which plays a vital role in various cellular processes, including DNA repair, chromosome segregation, and immunity. The complex is involved in the repair of DNA double-strand breaks through homologous recombination, facilitating sister chromatid homologous recombination by recruiting the SMC1-SMC3 cohesin complex to the breaks. The complex is essential for telomere maintenance via recombination in ALT (alternative lengthening of telomeres) cell lines, where it mediates sumoylation of shelterin complex (telosome) components, leading to their disassembly in ALT-associated PML bodies (APBs). Additionally, SMC5 is required for recruiting telomeres to PML nuclear bodies and plays a role in maintaining sister chromatid cohesion during prometaphase and mitotic progression. The SMC5-SMC6 complex may prevent the transcription of episomal DNA, such as circular viral DNA genomes. The complex has been implicated in interactions with various proteins, including NSMCE2, SLF2, RAD18, Hepatitis B X protein, and human herpesvirus 8 (KSHV) protein RTA/ORF50. These interactions highlight its role in regulating diverse cellular processes. The SMC5/6 complex was discovered in fission yeast and consists of SMC5, SMC6, and six nonstructural maintenance of chromosomes (NSE) proteins. The Nse1-Nse3-Nse4 subunits bridge the Smc5 head Smc6 and enable DNA binding. SMC5 is involved in the alternative lengthening of telomeres (ALT) cancer mechanism.
SMC5 is a core component of the SMC5-SMC6 complex, which plays a crucial role in repairing DNA double-strand breaks through homologous recombination. This complex may facilitate sister chromatid homologous recombination by recruiting the SMC1-SMC3 cohesin complex to these breaks. Additionally, it is essential for telomere maintenance via recombination in ALT (alternative lengthening of telomeres) cell lines. The complex mediates sumoylation of shelterin complex (telosome) components, leading to shelterin complex disassembly in ALT-associated PML bodies (APBs). SMC5 is required for recruiting telomeres to PML nuclear bodies and plays a role in maintaining sister chromatid cohesion during prometaphase and mitotic progression, independent of SMC6. The SMC5-SMC6 complex may prevent transcription of episomal DNA, such as circular viral DNA genomes.
SMC5 is also known as ATELS2, SMC5L1.
