Transcriptional Control of Hepatocanalicular Transporter

Bile formation is a regulated ATP-dependent pro-cess that depends on the coordinated action of a number of transporter proteins in the sinusoidal and canalicular domains of the hepatocyte.1–3 Transporter proteins lo-cated in the canalicular membrane are responsible for the rate-limiting and tightly coupled biliary secretion of bile salts, phosphatidylcholine (PC), unesterified cho-lesterol, and reduced glutathione (GSH) on the one hand and for the excretion of potentially toxic endogenous and exogenous compounds on the other hand (Fig. 1). These transporter proteins such as the bile salt trans-porter BSEP, the PC translocator MDR3, the anionic conjugate transporter MRP2, and the multidrug trans-porter MDR1 all belong to the superfamily of ATP