Disease relevance of MSRB2

• An epitope-directed antibody to an amino acid sequence at the carboxyl terminus of CBS-1 recognized a main protein of 19.5kDa in ocular ciliary body extracts, and a 23kDa protein in total extracts from E. coli MC1061 cells, which expresses high levels of MsrA [1].
• Interestingly, CBS-1 also shares significant identity with the carboxyl terminus of the peptide-methionine sulfoxide reductase (MsrA), a repair enzyme, from Helicobacter pylori and Streptococcus pneumoniae [1].

High impact information on MSRB2

• MsrB2 (CBS-1) resided in mitochondria [2].
• The peptide methionine sulfoxide reductases, MsrA and MsrB (hCBS-1), are downregulated during replicative senescence of human WI-38 fibroblasts [3].
• The expression of MsrA and one member of the MsrB family, hCBS-1, was analyzed during replicative senescence of WI-38 human fibroblasts [3].
• These results suggest that downregulation of MsrA and hCBS-1 can alter the ability of senescent cells to cope with oxidative stress, hence contributing to the age-related accumulation of oxidative damage [3].
• Activity, tissue distribution and site-directed mutagenesis of a human peptide methionine sulfoxide reductase of type B: hCBS1 [4].

Biological context of MSRB2

• The CBS-1 gene was mapped to human chromosome 10p12 between markers WI-8535 and WI-4724, and is tightly linked to the two STRP markers of D10S1789 and D10S550 [1].
• Here we report the isolation, characterization and chromosome localization of a subtracted cDNA (CBS-1) isolated from the human ocular ciliary body which encodes a novel protein [1].
• As is deduced from the nucleotide sequence of the cDNA, CBS-1 contains an open reading frame consisting of 182 amino acids, with a molecular weight of 19.5kDa [1].
• In RPE cells exposed to varying doses of H(2)O(2), gene expression of MsrA and hCBS-1 (the human analog of MsrB2) increased in a dose-dependent and time-dependent manner with maximal increase with 150 microM H(2)O(2) in 24h [5].

Anatomical context of MSRB2

• As previously found for hMSRB1, expression of hMSRB2 mRNA was weak in brain, but strong in heart and skeletal muscle [6].

Associations of MSRB2 with chemical compounds

• Human CBS1 is a methionine sulfoxide reductase of type B (MSRB) as it specifically reduced Met-R-SO in peptides with dithiothreitol or the thioredoxin system as reductants [4].
• A second human methionine sulfoxide reductase (hMSRB2) reducing methionine-R-sulfoxide displays a tissue expression pattern distinct from hMSRB1 [6].

Other interactions of MSRB2

• The kidney contains only CBS 1 and CBS 2 [7].

Analytical, diagnostic and therapeutic context of MSRB2

• By Northern blot, CBS-1, hybridized to a 0.6 to 0.7kb transcript in size, is expressed ubiquitously in many tissues, but most abundantly in the retina and ocular ciliary body, skeletal muscle and heart [1].

References