Polarized expression of members of the solute carrier SLC19A gene family of water-soluble multivitamin transporters: implications for physiological function.
Humans lack biochemical pathways for the synthesis of the micro-nutrients thiamine and folate. Cellular requirements are met through membrane transport activity, which is mediated by proteins of the SLC19A gene family. By using live-cell confocal imaging methods to resolve the localization of all SLC19A family members, we show that the two human thiamine transporters are differentially targeted in polarized cells, establishing a vectorial transport system. Such polarization decreases functional redundancy between transporter isoforms and allows for independent regulation of thiamine import and export pathways in cells.
Boulware
Michael J
MJ
Department of Pharmacology, 321 Church Street SE, University of Minnesota Medical School, MN 55455, USA.
Subramanian
Veedamali S
VS
Said
Hamid M
HM
Marchant
Jonathan S
JS
D000818:Animals; D001692:Biological Transport; D002460:Cell Line; D016764:Cell Polarity; D004285:Dogs; D005492:Folic Acid / Q000378:metabolism; D006801:Humans; D026901:Membrane Transport Proteins / Q000032:analysis / Q000378:metabolism* / Q000502:physiology; D018613:Microscopy, Confocal; D012995:Solubility; D013831:Thiamine / Q000378:metabolism; D014867:Water / Q000737:chemistry
D026901:Membrane Transport Proteins; C120043:SLC19A2 protein, human; C492291:SLC19A3 protein, human; D014867:Water; D005492:Folic Acid; D013831:Thiamine