MITOCHONDRIAL RIBOSOMAL PROTEIN L13; MRPL13

Alternative titles; symbols

• RIBOSOMAL PROTEIN, MITOCHONDRIAL, L13; RPML13
• L13A

HGNC Approved Gene Symbol: MRPL13

Cytogenetic location: 8q24.12 Genomic coordinates (GRCh38): 8:120,395,436-120,445,149 (from NCBI)

▼ Cloning and Expression
Price et al. (1992) identified a human cDNA fragment homologous to the mouse transplantation antigen P198. By PCR of a promyelocytic (HL-60) cell line cDNA library, they obtained a full-length cDNA encoding MRPL13, which they called p23. The predicted 203-amino acid protein has a calculated molecular mass of 23.6 kD and is rich in lysine and arginine. It shares 94% amino acid identity with the mouse and bovine proteins. Northern blot analysis detected 1.2- and 0.8-kb transcripts in human brain. Expression of Mrpl13 was ubiquitous in bovine tissues.

A gamma-interferon (IFNG; 147570)-activated inhibitor of translation (GAIT) element in the 3-prime UTR of ceruloplasmin (CP; 117700) is required for IFNG-mediated silencing of CP translation. By yeast 3-hybrid analysis of an IFNG-activated monocyte (U937) cell line cDNA library using the 3-prime UTR of CP coupled with MS2 (ADAM8; 602267) RNA as bait, Mazumder et al. (2003) isolated MRPL13. The MRPL13 protein has an N-terminal leucine zipper and a basic leucine zipper domain in its C-terminal half.

▼ Gene Function
Mazumder et al. (2003) found that treatment of U937 cells with IFNG induced phosphorylation of MRPL13 and led to its release from the 60S ribosomal subunit. Released MRPL13 specifically bound the GAIT element in the 3-prime UTR of CP and silenced CP translation. Mazumder et al. (2003) proposed that the ribosome functions not only as a protein synthesis machine, but also as a depot for regulatory proteins that modulate translation.

Kapasi et al. (2007) showed that the GAIT complex protein L13A blocked CP mRNA translation in U937 cells by preventing assembly of the 80S ribosomal complex. L13A bound EIF4G (EIF4G1; 600495) at its EIF3 (see EIF3S1; 603910)-binding site and interfered with recruitment of 43S to the ribosomal complex. Phosphorylation of L13A was required for its activity.

▼ Mapping
By radiation hybrid analysis, Kenmochi et al. (2001) mapped the MRPL13 gene to chromosome 8q22.1-q22.3.