Mothers against decapentaplegic homolog 3 (SMAD3)

Receptor-regulated SMAD (R-SMAD) which is an intracellular signal transducer and transcriptional modulator activated by TGF-beta (transforming growth factor) and activin type 1 receptor kinases. Binds the TRE element in the promoter region of several genes which are regulated by TGF-beta and, on formation of the SMAD3/SMAD4 complex, activates transcription.

Also can form a SMAD3/SMAD4/JUN/FOS complex at the AP-1/SMAD site to regulate TGF-beta-mediated transcription. Has an inhibitory effect on wound healing probably by modulating both growth and migration of primary keratinocytes and by changing the TGF- mediated chemotaxis of monocytes.