The function of ENSG00000164638 (SLC29A4, solute carrier family 29 member 4) is as follows. Electrogenic voltage-dependent transporter that mediates the transport of a variety of endogenous bioactive amines, cationic xenobiotics and drugs (PubMed:15448143, PubMed:16099839, PubMed:16873718, PubMed:17018840, PubMed:17121826, PubMed:20592246, PubMed:20858707, PubMed:22396231, PubMed:31537831). Utilizes the physiologic inside-negative membrane potential as a driving force to facilitate cellular uptake of organic cations (PubMed:15448143, PubMed:20592246, PubMed:22396231). Functions as a Na(+)- and Cl(-)- independent bidirectional transporter (PubMed:15448143, PubMed:16099839, PubMed:22396231, PubMed:31537831). Substrate transport is pH-dependent and enhanced under acidic condition, which is most likely the result of allosteric changes in the transporter structure (PubMed:16873718, PubMed:17018840, PubMed:20592246, PubMed:22396231, PubMed:31537831). Implicated in monoamine neurotransmitters uptake such as serotonin, dopamine, adrenaline/epinephrine, noradrenaline/norepinephrine, histamine and tyramine, thereby supporting a role in homeostatic regulation of aminergic neurotransmission in the central nervous system (PubMed:15448143, PubMed:16099839, PubMed:17018840, PubMed:17121826, PubMed:20858707, PubMed:22396231). Also responsible for the uptake of bioactive amines and drugs through the blood-cerebrospinal fluid (CSF) barrier, from the CSF into choroid plexus epithelial cells, thereby playing a significant role in the clearance of cationic neurotoxins, xenobiotics and metabolic waste in the brain (By similarity). Involved in bidirectional transport of the purine nucleoside adenosine and plays a role in the regulation of extracellular adenosine concentrations in cardiac tissues, in particular during ischemia (PubMed:16873718, PubMed:20592246, PubMed:31537831). May be involved in organic cation uptake from the tubular lumen into renal tubular cells, thereby contributing to organic cation reabsorption in the kidney (PubMed:17018840). Also transports guanidine (PubMed:16099839). {ECO:0000250|UniProtKB:Q8R139, ECO:0000269|PubMed:15448143, ECO:0000269|PubMed:16099839, ECO:0000269|PubMed:16873718, ECO:0000269|PubMed:17018840, ECO:0000269|PubMed:17121826, ECO:0000269|PubMed:20592246, ECO:0000269|PubMed:20858707, ECO:0000269|PubMed:22396231, ECO:0000269|PubMed:31537831}.