Ribosomes,the complexes that catalyze protein synthesis,consist of a small 40S subunit and a large 60S subunit. Together these subunits are composed of 4 RNA species and approximately 80 structurally distinct proteins. RPL3,also named as TARBP-B and MGC104284,belongs to the ribosomal protein L3P family. This protein is a component of the 60S subunit. It can bind to the HIV-1 TAR mRNA,and it has been suggested that the protein contributes to tat-mediated transactivation. As is typical for genes encoding ribosomal proteins,there are multiple processed pseudogenes of this gene dispersed through the genome.