Recombinant Proteins
Product List
SMAD2 Human
SMAD Family Member 2 Human Recombinant
SMAD3 Human
Mothers Against Decapentaplegic Homolog 3 Human Recombinant
SMAD4 Human
Mothers Against Decapentaplegic Homolog 4 Human Recombinant
Introduction
SMAD proteins are a family of structurally similar proteins that act as the main signal transducers for receptors of the transforming growth factor beta (TGF-β) superfamily. These proteins are crucial for regulating cell development and growth . The name “SMAD” is derived from the homologies to the Caenorhabditis elegans SMA (small worm phenotype) and MAD (Mothers Against Decapentaplegic) family of genes in Drosophila . SMAD proteins are classified into three sub-types:
SMAD proteins are approximately 400-500 amino acids long and consist of two globular regions at the amino and carboxy termini, connected by a linker region . They are primarily located in the cytoplasm but accumulate in the nucleus following TGF-β signaling . R-SMADs and Co-SMADs are involved in direct signaling from the TGF-β receptor, while I-SMADs suppress the activity of R-SMADs . SMAD proteins are expressed in various tissues and play a critical role in cell development and growth .
SMAD proteins are essential for regulating cell development, growth, and differentiation . They play a central role in integrating TGF-β and BMP signaling with other essential pathways . SMAD proteins are involved in immune responses and pathogen recognition by regulating the expression of genes involved in these processes . They also play a role in the development of the nervous system and the generation of neurological diseases .
SMAD proteins function as transcription factors and their activities require carboxyl-terminal phosphorylation by TGF-β receptor kinases . Phosphorylation of R-SMADs causes them to dissociate from SARA (SMAD anchor for receptor activation), exposing a nuclear import sequence and promoting their association with Co-SMADs . The SMAD complex then localizes to the nucleus, where it binds to target genes with the help of other associated proteins . I-SMADs negatively regulate R-SMAD signaling by competing for binding to activated type I receptors and inhibiting R-SMAD phosphorylation .
The expression and activity of SMAD proteins are regulated by various mechanisms, including transcriptional regulation and post-translational modifications . Phosphorylation, ubiquitination, sumoylation, acetylation, and poly (ADP)-ribosylation are some of the post-translational modifications that regulate SMAD activity and stability . I-SMADs inhibit the phosphorylation of R-SMADs and promote the ubiquitination and degradation of receptor complexes, thus inhibiting signaling .
SMAD proteins have significant applications in biomedical research, diagnostic tools, and therapeutic strategies . They are central to the TGF-β signaling pathway, which plays a dual role in cancer progression as both an inhibitor of tumor cell growth and an inducer of tumor metastasis . SMAD proteins are also involved in nerve regeneration and the development of therapeutic strategies for neurological diseases .
SMAD proteins play a crucial role throughout the life cycle, from development to aging and disease . They are involved in the development of the nervous system, neuralization of ectodermal cells, and specification of cell types . SMAD proteins also play a role in the generation of neurological diseases and are considered therapeutic targets for the treatment of these diseases .
