SMAD3 Protein, Human/Mouse/Rat (Flag-His)

SMAD3 protein functions as a receptor-regulated SMAD (R-SMAD), serving as an intracellular signal transducer and transcriptional modulator activated by TGF-beta and activin type 1 receptor kinases. Upon activation by antigen-presenting cells, SMAD3 binds the TRE element in gene promoters regulated by TGF-beta and, in conjunction with SMAD4, forms a complex that activates transcription. Additionally, it can assemble a SMAD3/SMAD4/JUN/FOS complex at the AP-1/SMAD site to regulate TGF-beta-mediated transcription. SMAD3 exhibits an inhibitory effect on wound healing, potentially by modulating the growth and migration of primary keratinocytes and altering TGF-mediated monocyte chemotaxis, and this effect appears to be hormone-sensitive. Moreover, SMAD3 serves as a regulator of chondrogenesis and osteogenesis and inhibits early healing of bone fractures. It positively regulates PDPK1 kinase activity by dissociating it from the 14-3-3 protein YWHAQ, acting as a negative regulator. In the absence of TGF-beta, SMAD3 exists as a monomer, whereas in the presence of TGF-beta, it forms homooligomers or heterotrimers, contributing to the versatility of its functions. SMAD3 engages in a complex interaction network with various proteins, including but not limited to MAGI2/ARIP1, ACVR2A, ACVR1B, JUN, FOS, RAN, XPO4, NEDD9, ITCH/AIP4, NEDD9/HEF1, ZNF451, PPM1A, ZMIZ1, RNF111, RANBP3, EP300, TGFBR1, TGFB1I1, PRDM16, SNW1, ZFYVE9, HDAC1, TGIF2, SKOR1, SKOR2, DACH1, RBPMS, MECOM, WWTR1, SKI, MEN1, IL1F7, CSNK1G2, PDPK1, DAB2, USP15, PPP5C, LDLRAD4, PMEPA1, ZNF451, ZFHX3, ZNF8, STUB1, HSPA1A, HSPA1B, HSP90AA1, HSP90AB1, YAP1, CITED2, HGS, WWP1, TTRAP, FOXL2, PML, NEDD4L, ZC3H3, TGIF, CREBBP, ATF2, NEDD9, and more, highlighting its central role in diverse cellular processes and signaling pathways.