Na /monocarboxylate transport (SMCT) protein expression correlates with survival in colon cancer: Molecular characterization of SMCT

Abstract

We report an extensive characterization of the Na+/ monocarboxylate transporter (SMCT), a plasma membrane protein that mediates active transport of monocarboxylates such as propionate and nicotinate, and we show that SMCT may play a role in colorectal cancer diagnosis. SMCT, the product of the SLC5A8 gene, is 70% similar to the Na+/I- symporter, the protein that mediates active I- uptake in the basolateral surface of thyrocytes and other cells. SMCT was reported in the apical surface of thyrocytes and formerly proposed also to transport I - and was called the apical I- trans-porter. However, it is now clear that SMCT does not transport I-. Here we demonstrate a high-affinity Na+-dependent mo..