SMAD1
SMAD1 (SMAD family member 1, also known as MADR1, JV4-1 and MADH1) is an intracellular signal transducer and transcriptional modulator that relays bone morphogenetic protein (BMP) signals from the cell surface to the nucleus. Browse Assay Genie's current range of SMAD1 research reagents below, or read on for the biology behind the target.
SMAD1 acts as a transcriptional modulator in embryonic development, cell differentiation and tissue homeostasis. When BMP ligands bind their receptors at the cell surface, SMAD1 is phosphorylated by the activated type I BMP receptors. It then associates with SMAD4 to form a heteromeric complex that translocates into the nucleus and acts as a transcription factor. In the nucleus, the complex recognises cis-regulatory elements containing Smad Binding Elements (SBEs) and modulates the output of the signalling network.
The SMAD1 gene encodes a member of the dwarfin/SMAD family, whose proteins resemble the products of the Drosophila gene 'mothers against decapentaplegic' (Mad) and the C. elegans gene Sma. The protein is found in both the cytoplasm and the nucleus, consistent with its role in shuttling signals between the two. Alternatively spliced transcript variants encoding the same protein have been reported. Mouse and rat both have a Smad1 ortholog.
BMPs regulate cell growth, apoptosis, morphogenesis, development and immune responses, and SMAD1 mediates these signals. Other described functions include a SMAD1/OAZ1/PSMB4 complex that mediates degradation of SNIP1, a repressor of CREBBP/EP300, and positive regulation of BMP4-induced expression of the odontogenic regulator MSX1 after IPO7-mediated nuclear import. SMAD1 is itself a target for the SMAD-specific E3 ubiquitin ligases SMURF1 and SMURF2, which direct its ubiquitination and proteasome-mediated degradation. Earlier names for the gene include MAD and SMAD, mothers against DPP homolog 1 (Drosophila).
SMAD1 is phosphorylated by type I BMP receptors, making it a central readout of BMP pathway activation.
SMAD1 contributes to embryonic development, cell differentiation and tissue homeostasis, including BMP4-induced MSX1 expression in odontogenic development.
The SMAD1–SMAD4 complex binds Smad Binding Elements to modulate gene expression, a model for studying SMAD-dependent transcription.
SMURF1 and SMURF2 target SMAD1 for proteasomal degradation, linking it to studies of E3 ligase control of signalling.
SMAD1 transduces BMP signals. After phosphorylation by activated type I BMP receptors, it forms a complex with SMAD4, moves into the nucleus and modulates transcription by recognising Smad Binding Elements. It supports embryonic development, differentiation and tissue homeostasis.
SMAD1 is also known as MADR1, JV4-1 and MADH1. Earlier names include MAD and SMAD, mothers against DPP homolog 1 (Drosophila), reflecting its similarity to the Drosophila gene 'mothers against decapentaplegic'. The gene is reported to give alternatively spliced transcripts encoding the same protein.
SMAD1 belongs to the dwarfin/SMAD family, related to Drosophila Mad and C. elegans Sma, and mouse and rat each have a Smad1 ortholog. Check the datasheet of any product for its validated reactivity.
Other SMAD family members, including the common partner SMAD4 and inhibitory SMADs, that act in BMP and TGF-β signalling.
Gene and protein annotations from HGNC, NCBI Gene and UniProt Q15797; product specifications from Assay Genie datasheets.