sma-4 encodes a Smad protein and a homolog of human DPC4, which when mutated leads to pancreatic carcinoma (OMIM:260350); SMA-4 is similar to members of the vertebrate protein family of Dwarfins; during development, sma-4 functions as part of a DBL-1/SMA-6 TGF-beta-related signaling pathway that controls body size and male tail sensory ray and spicule formation; sma-4, through this pathway, also regulates reproductive aging; studies have shown that a reduction of TGF-beta pathway genes extends reproductive span by maintaining oocyte and germline quality; SMA-4 can physically interact with the RNT-1/RUNX transcription factor, which interacts and functions with the TGF-beta signaling pathway, in regulating body size and male tail development.
Predicted to enable DNA-binding transcription factor activity, RNA polymerase II-specific; I-SMAD binding activity; and RNA polymerase II cis-regulatory region sequence-specific DNA binding activity. Involved in several processes, including determination of adult lifespan; nematode male tail tip morphogenesis; and positive regulation of growth. Predicted to be located in cytoplasm and nucleus. Predicted to be part of heteromeric SMAD protein complex. Expressed in head neurons and pseudocoelom. Human ortholog(s) of this gene implicated in several diseases, including carcinoma (multiple); colorectal adenoma; and female reproductive organ cancer (multiple). Is an ortholog of human SMAD4 (SMAD family member 4).