Alternative titles; symbols
HGNC Approved Gene Symbol: SAMM50
Cytogenetic location: 22q13.31 Genomic coordinates (GRCh38): 22:43,955,442-43,996,529 (from NCBI)
SAMM50 is a component of the sorting and assembly machinery (SAM) complex of the outer mitochondrial membrane. The SAM complex has a role in integrating beta-barrel proteins into the outer mitochondrial membrane (Humphries et al., 2005).
Humphries et al. (2005) found that continued expression of fluorescence-tagged human SAM50 in COS-7 cells impaired mitochondrial morphology and shortened cellular life span, indicating that the fusion protein was toxic. SAM50 was associated with a 200-kD protein complex that was distinct from the 380-kD translocase of the outer mitochondrial membrane (TOM) complex. RNA interference against SAM50 in human embryonic kidney cells reduced assembly of TOM40 (TOMM40; 608061), an essential component of the TOM complex involved in translocation and sorting of proteins into mitochondria.
Using a monoclonal antibody directed against the mitochondrial inner membrane protein mitofilin (IMMT; 600378), followed by SDS-PAGE and mass spectrometry, Xie et al. (2007) identified a protein complex in human heart mitochondria that, in addition to mitofilin, included SAMM50, metaxin-1 (MTX1; 600605), metaxin-2 (MTX2; 608555), CHCHD3 (613748), CHCHD6 (615634), and DNAJC11 (614827).
Hartz (2014) mapped the SAMM50 gene to chromosome 22q13.31 based on an alignment of the SAMM50 sequence (GenBank AF151809) with the genomic sequence (GRCh37).
Hartz, P. A. Personal Communication. Baltimore, Md. 2/7/2014.
Humphries, A. D., Streimann, I. C., Stojanovski, D., Johnston, A. J., Yano, M., Hoogenraad, N. J., Ryan, M. T. Dissection of the mitochondrial import and assembly pathway for human Tom40. J. Biol. Chem. 280: 11535-11543, 2005. [PubMed: 15644312] [Full Text: https://doi.org/10.1074/jbc.M413816200]
Xie, J., Marusich, M. F., Souda, P., Whitelegge, J., Capaldi, R. A. The mitochondrial inner membrane protein mitofilin exists as a complex with SAM50, metaxins 1 and 2, coiled-coil-helix coiled-coil-helix domain-containing protein 3 and 6 and DnaJC11. FEBS Lett. 581: 3545-3549, 2007. [PubMed: 17624330] [Full Text: https://doi.org/10.1016/j.febslet.2007.06.052]