Na+/I- cotransport (influx) by the Na+/I- symporter Authored: Jassal, B, 2009-07-17 Edited: Jassal, B, 2009-07-17 Human SLC5A5 encodes a Na+/I- symporter, NIS (Smanik PA et al, 1996). NIS is localized in the basolateral membrane facing the bloodstream and mediates iodide accumulation into thyrocytes.Defects in SLC5A5 cause congenital hypothyroidism due to dyshormonogenesis type 1 (CHDH1) (Fujiwara H et al, 1997). NIS, together with AIT (see next reaction), mediates iodide transfer from blood to the colloid lumen of thyrocytes. Pubmed8806637 Pubmed9171822 Reactome Database ID Release 43429591 Reactome, http://www.reactome.org ReactomeREACT_19340 Reviewed: He, L, 2009-08-24