The function of TRPS1 in the development and differentiation of bone, kidney, and hair follicles.

TRPS1 is a gene involved in Tricho-rhino-phalangeal syndrome (TRPS), an autosomal dominant skeletal disorder. TRPS1 encodes a GATA-type transcription factor that has nine zinc-finger motifs. A variety of mutations in TRPS1 including deletions and insertions, have been found in patients with TRPS type I and III. The functions of each domain of TRPS1 have been clarified from study of these mutations. Further studies on the localization and the function of TRPS1 have been performed using TRPS1Δgt and Trps1-deficient mice, which allow examination of the development and differentiation of all tissues with Trps1 expression. These studies suggest that TRPS1 exhibits a variety of functions in cartilage, kidneys, and hair follicles. In the growth plate cartilage, TRPS1 regulates the differentiation, proliferation, and apoptosis of chondrocytes through interaction of several signaling molecules. In addition, TRPS1 has a function downstream of BMP7, which regulates the mesenchymal-epithelial transition when nephrons are formed in renal development. Furthermore, TRPS1 suppresses the epithelial-mesenchymal transition and renal fibrosis induced by unilateral ureteral obstruction by decreasing Arkadia expression. Finally, TRPS1 is expressed in the dermal papillae and the mesenchymal cells surrounding the hair pegs, and the loss of TRPS1 largely influences the development of hair follicles. The molecular mechanisms of the function of TRPS1 in cartilage, kidneys, and hair follicles are discussed in this review.