Author: Aoi Yamamoto
Short Communication
Role of Epithelial Cell Polarity in Nucleoside Transport Across Biological Barriers
Aoi Yamamoto*
Department of Cell Biology, Kyoto University, Kyoto, Japan
Published: 23 July 2021
Abstract
Epithelial cells form continuous, polarized sheets that line organs and body cavities, playing critical roles in selective barrier function and substance exchange. Their polarity defined by distinct apical and basolateral membrane domains is essential for vectorial transport processes, including the regulated absorption and secretion of nucleosides such as adenosine, cytidine, guanosine, uridine, and thymidine. These nucleosides serve not only as building blocks for nucleic acids but also as signaling molecules and metabolic intermediates, transported across epithelial barriers by two key transporter families: SLC28 (CNTs) and SLC29 (ENTs). CNTs are sodium-dependent, high-affinity, apically localized transporters with subtype-specific preferences for purine or pyrimidine nucleosides, while ENTs are facilitative, bidirectional transporters found predominantly on basolateral membranes.
