SMAD2

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

SMAD2 is a human protein produced by the SMAD2 gene. It belongs to the SMAD family, which carries signals from outside the cell to the nucleus to control gene activity in response to TGF-beta signals that regulate cell growth, death, and differentiation.

Activation happens when TGF-beta (and related ligands like activin) bind to receptors on the cell surface. The receptors phosphorylate SMAD2 at its C-terminus, causing SMAD2 to release from SARA and pair with SMAD4. The SMAD2–SMAD4 complex then moves into the nucleus, where it helps regulate target genes, often by forming a transcriptional repressor complex with other cofactors.

SMAD2 can also be phosphorylated by activin receptor kinases, linking it to activin signaling. There are multiple transcript variants due to alternative splicing, but they encode the same SMAD2 protein.

SMAD2 has orthologs in other species, including mice. In humans, the SMAD2 gene is located on chromosome 18 (18q21.1). The name SMAD comes from a combination of Drosophila and C. elegans gene names (MAD and SMA) and reflects a historical naming tradition in genetics.

Dysregulation of SMAD2 and TGF-beta signaling is linked to various diseases, including cancer and fibrosis.