由該基因編碼的蛋白質屬于smad，一個類似于果蠅基因‘母親抗十五癱’（mad）和秀麗隱桿線蟲基因sma的基因產物的蛋白質家族。smad蛋白是介導多種信號通路的信號轉導和轉錄調節因子。這種蛋白作為一種轉錄調節劑，被轉化生長因子β激活，并被認為在致癌過程中發揮調節作用。[由RefSeq提供，2009年4月]
The protein encoded by this gene belongs to the SMAD, a family of proteins similar to the gene products of the Drosophila gene 'mothers against decapentaplegic' (Mad) and the C. elegans gene Sma. SMAD proteins are signal transducers and transcriptional modulators that mediate multiple signaling pathways. This protein functions as a transcriptional modulator activated by transforming growth factor-beta and is thought to play a role in the regulation of carcinogenesis. [provided by RefSeq, Apr 2009]