I-SMAD or Inhibitor SMAD is a subclass of SMADs that are involved in the modulation of transforming growth factor beta ligands. This class includes SMAD6 and SMAD7. They compete with SMAD4 and consequently regulate the transcription of its gene products.

• SMAD (protein)
• R-SMAD

• I-Smad+Proteins at the U.S. National Library of Medicine Medical Subject Headings (MeSH)