Translocates a broad array of organic cations with various structures and molecular weights including the model compounds 1-methyl-4-phenylpyridinium (MPP), tetraethylammonium (TEA), N-1-methylnicotinamide (NMN), 4-(4-(dimethylamino)styryl)-N-methylpyridinium (ASP), the endogenous compounds choline, guanidine, histamine, epinephrine, adrenaline, noradrenaline and dopamine, and the drugs quinine, and metformin. The transport of organic cations is inhibited by a broad array of compounds like tetramethylammonium (TMA), cocaine, lidocaine, NMDA receptor antagonists, atropine, prazosin, cimetidine, TEA and NMN, guanidine, cimetidine, choline, procainamide, quinine, tetrabutylammonium, and tetrapentylammonium. Translocates organic cations in an electrogenic and pH-independent manner. Translocates organic cations across the plasma membrane in both directions. Transports the polyamines spermine and spermidine. Transports pramipexole across the basolateral membrane of the proximal tubular epithelial cells. The choline transport is activated by MMTS. Regulated by various intracellular signaling pathways including inhibition by protein kinase A activation, and endogenously activation by the calmodulin complex, the calmodulin-dependent kinase II and LCK tyrosine kinase. Within sinusoidal membrane of hepatocytes. Expressed in kidney, kidney cortex, kidney medulla, liver, intestine and colon. Expressed in proximal tubules in kidney, hepatocytes in liver and enterocytes of villi and crypts in smallintestine. Expressed throughout the liver lobuli. Expressed in hepatocytes surrounding the central veins (at protein level). Expressed in S1, S2 segments of proximal tubules in kidney (at protein level). Highly expressed in kidney and spleen, moderately in skin, and weakly in the gastrointestinal tract, brain, lung, thymus, muscle, and prostate. Weakly expressed in some white matter regions like the corpus callosum and in the granular layer of the cerebellum. Renal level increases gradually from postnatal day 1 through day 45 in both genders. Down-regulated in obstructive cholestasis. Up-regulated by treatment with pregnenolone-16 alpha-carbonitrile (PCN) and by overexpression of pregnane X receptor (PXR). Phosphorylated. Belongs to the major facilitator (TC 2.A.1) superfamily. Organic cation transporter (TC 2.A.1.19) family.