Session: Current Topics in Biological Chemistry:

Protein tyrosine sulfation is a post-translational modification that plays important roles in diverse cellular activities. Sulfated proteins have been reported to be involved in cell adhesion, leukocyte trafficking, hormone activities, and immune responses. To facilitate the study of protein sulfation in mammalian cells, we recently developed a method to site-specifically incorporate sulfotyrosine into any proteins using an engineered tyrosyl-tRNA synthetase derived from E. coli (EcTyrRS). The engineered EcTyrRS was selected in Saccharomyces cerevisiae, and then examined in HEK293T cells using eGFP as the reporter protein. To demonstrate the functionality of our system, sulfotyrosine was incorporated at position 21 of the chemokine receptor CXCR4. The calcium mobilization assay validated that sulfation at Tyr21 position of CXCR4 is important for the activation of this receptor by its chemokine ligand SDF-1. For future applications, our system will facilitate the study of protein sulfation-associated eukaryotic signaling processes and the development of diagnostic and therapeutic agents targeting protein sulfation.

Justin Lawrie

Appearances