TJP1 (Tight junction protein-1, Zonula occludens-1, ZO-1) is a scaffold protein involved in tight junction assembly, anchoring and stabilization. It functions in cell-cell junction signal transduction and in the regulation of cell migration by targeting CDC42BPB to the leading edge of migrating cells. TJP1 is upregulated in and drug-resistant multiple myeloma, and is associated with a higher risk subset of cancers. TJP1 has been found to be upregulated in drug-resistant tumors. In immunohistochemistry of normal tissue, TJP1 has membranous positivity in endothelial cells, glandular epithelia, renal glomeruli, sertoli cells, and is expressed in most tissues throughout the body. References: The UniProt Consortium. Nucleic Acids Res. 47: D506-515 (2019); Nucleic Acids Res. 2016 Jan 4;44(D1):D733-45, PMID:26553804; Oncoscience. 2017 Jul; 4(7-8): 79–94, PMID: 28966941