Ubiquitination regulation of histidine transporter Hip1p on histidine utilization in Saccharomyces cerevisiae

Abstract:

[Objective] In order to demonstrate the ubiquitination regulation mechanism of histidine transporters. [Methods] By both ubiquitination sites prediction and site-directed mutagenesis, 3 potential ubiquitination sites, K30, K42 and K42 of Hip1p were mutated. These Hip1p mutants were cloned into the ubiquitination detection plasmid for measuring its ubiquitination level change. Effects of these mutants on both cell growth and histidine utilization were measured. [Results] By comparing the relative fluorescence of Hip1p and its mutants, ubiquitination sites mutation reduced the ubiquitination levels of Hip1p. Furthermore, double mutation of ubiquitination sites showed a synergy effect on reducing ubiquitination level. The ubiquitination sites mutants also influenced cell growth and enhance histidine utilization when histidine was used as the sole nitrogen source. [Conclusion] The ubiquitination levels could regulate the histidine metabolism and change the pattern for histidine metabolism, and provide clues for further investigation of regulation mechanisms involved in the amino acids transporter proteins.