Tyrosine Sulfation in Voltage-Gated Potassium Channels

Student Name: Christina Ji

UCD Department: Neurobiology, Physiology, and Behavior

UCD Mentor: Dr. Grace Rosenquist

Tyrosine sulfation is a posttranslational modification of a protein in which the hydroxyl group of the amino acid tyrosine is changed into a sulfate group. This modification strengthens protein-protein interaction. Tyrosine sulfation is prominent in the signature sequence of the conserved selectivity filter of voltage-gated potassium channels. The functionally similar KcsA from bacteria Streptomyces lividans shares this signature sequence. Positively charged toxin binding sites interact with negatively charged sulfated tyrosine sites. Voltage-gated potassium channels function in repolarization of action potentials in the brain, heart, and muscles. Tyrosine sulfation plays a critical role in the conduction of these channels.