Fragile X Mental Retardation Syndrome Related Protein 2 (FXR2)

FXR2 is an RNA binding protein containing two KH domains and one RCG box, which is similar to FMRP and FXR1. It associates with polyribosomes, predominantly with 60S large ribosomal subunits. This encoded protein may self-associate or interact with FMRP and FXR1. It may have a role in the development of fragile X mental retardation syndrome. Sequence analysis predicted that the 673-amino acid protein, with high N-terminal homology to FMR1 and FXR1 and approximately 60% identity overall, contains 2 ribonucleoprotein K homology (KH) domains, which are involved in RNA binding. FXR2 is expressed as a 3.0-kb transcript in HeLa cells and in mouse brain. Immunoblot analysis showed that FXR2 is expressed as a 95-kD protein, although the predicted molecular weight was 74 kD.