SMURF1 and osteoporosis: A number of in vivo and in vitro studies have shown associations of SMURF1 (Smad Ubiquitin Regulatory Factor-1) with osteoblast function and response to BMPs (bone morphogenetic proteins) (27, 28), and genetic variants in the genes encoding SMURF1-related proteins have been implicated in the risk of osteoporosis by hypothesis-free GWAS (29).