Phenylalanine–tRNA ligase alpha subunit, also called phenylalanyl-tRNA synthetase alpha chain, is an enzyme that in humans is encoded by the FARSA gene. Two copies each of this protein and FARSB bind together to form a heterotetramer complex that functions as a Phenylalanine–tRNA ligase in the cytoplasm. This means it participates in RNA-to-protein translation by attaching the amino acid phenylalanine to the corresponding type of transfer RNA, tRNA(Phe).
Function
Aminoacyl-tRNA synthetases are a class of enzymes that charge tRNAs with their cognate amino acids. This gene encodes a product which is similar to the catalytic subunit of prokaryotic and Saccharomyces cerevisiae phenylalanyl-tRNA synthetases (PheRS). This gene product has been shown to be expressed in a tumor-selective and cell cycle stage- and differentiation-dependent manner, the first member of the tRNA synthetase gene family shown to exhibit this type of regulated expression
Medical significance Pathogenic mutations in FARSA or FARSB are the cause of a disorder called Rajab interstitial lung disease with brain calcifications. The type caused by FARSA is denoted type 2 (RILDBC2), and is associated with growth delays, lung disease, and abnormal calcifications in the brain.
See also Phenylalanine–tRNA ligase, mitochondrial (FARS2) – analogous enzyme in the mitochondria
References
Further reading