In order to define subcellular localization of SDCT2, expression vector of SDCT2 and EGFP (enhanced green fluorescence protein) fusion protein was constructed and transfected into pig renal tubular epithelial cells LLC-PK1. Laser confocal microscopy showed that SDCT2 protein was almost exclusively located at the basal and lateral membranes of LLC-PK1 cells. When SDCT2-EGFP mRNA was microinjected into Xenopus oocytes, green fluorescence of the fusion protein was only found at the cellular membrane. To further determine subcellular localization signal of SDCT2, its N-terminal and C-terminal sequences were deleted and fused with EGFP. These deletion mutants were transfected into LLC-PK1 and their intracellular distributions were observed. The confocal analysis indicated that the SDCT2 with N-terminal deletion was predominantly distributed in the cytoplasm and also expressed at apical and basolateral membranes. The SDCT2 with C-terminal deletion was almost entirely distributed at the basolateral membrane, nearly not expressed at the apical membrane, and seldom expressed in the cytoplasm. Immunohistochemistry staining revealed that SDCT2 only expressed at the basolateral membrane of proximal renal tubular cells. The above results suggested that the N-terminus of SDCT2 is required for its subcellular localization and the basolateral membrane localization signal of SDCT2 locates in the N-terminal sequence.