May regulate the bone morphogenetic proteins (BMP) pathway. Found in a macromolecular complex with SMAD1. Interacts with SMAD1 (via MH2 domain); in a SMAD4-independent manner. Detected predominantly in cytosolic. Upon BMP stimulation, a small portion of PAWS1 is detected in the nucleus. BMP signaling induces the phosphorylation of PAWS1 by BMPR1A at Ser-610, Ser-614 and Ser-616. In response to BMP phosphorylation at Ser-610 is necessary for the activation of SMAD4-independent BMP target genes such as NEDD9 and ASNS. Belongs to the FAM83 family.