Involved in the establishment of cell polarity in mammalian epithelial cells . Regulates the morphogenesis of tight junctions . Involved in promoting phosphorylation and cytoplasmic retention of transcriptional coactivators YAP1 and WWTR1/TAZ which leads to suppression of TGFB1-dependent transcription of target genes such as CCN2/CTGF, SERPINE1/PAI1, SNAI1/SNAIL1 and SMAD7 (By similarity).
Apical cell membrane ; Single-pass type I membrane protein . Cell junction, tight junction . Localizes primarily to the apical membrane with a small fraction in the upper part of tight junctions of epithelial cells. .
Preferentially expressed in epithelial tissues (PubMed:14718572). Expressed at high levels in lung, kidney, and colon (PubMed:12527193, PubMed:14718572). Expressed at high levels in retina, colon and mammary glands (PubMed:12527193). Moderately expressed in liver, spleen, pancreas and prostate (PubMed:12527193). Moderately to weakly expressed in the placenta (PubMed:14718572, PubMed:12527193). Weakly expressed in skeletal muscle and small intestine (PubMed:14718572).