Organic anion transporters (OATs) are a group of transporters that interact with organic anionic molecules or zwitterions in our body. OATs mainly exist in the kidney and mediate the disposition of a wide range of endogenous physiological substances, exogenous clinical drugs and toxins. Thus, to understand the regulation of OATs has profound physiological and clinical significance. Like other proteins, OATs can be regulated at different levels from gene to protein, including at transcriptional, post-transcriptional, translational, and post-translational stages. This dissertation mainly focuses on the regulation of OATsat post-translational levels, specifically the role of ubiquitination in regulating OATs. In the first part, an overview of OATs and their regulation will be introduced. Several mechanisms underlying the post-translational regulation of OATs uncovered previouslyby our laboratory will be elaborated, including the regulation of OATs by ubiquitination. From the second to the fifth part, I will introduce our detailed investigation underlying protein kinase-regulated OAT ubiquitination and function; specific emphasis will be placed on identification of ubiquitin enzymes. In the last part, I will summarize about my research and propose the future direction for the study.