This application requests support for the 45th annual meeting of the ORS Sun Valley Workshop: Musculoskeletal Biology on Skeletal Biology held in Sun Valley, Idaho, August 2-5, 2015. The Workshops emphasize active participation of junior faculty and students; promote interdisciplinary communication; and are unusual in that discussion time equals or exceeds time allotted for formal presentation. The goals of the Workshop are to (1) work toward a multidisciplinary basic and clinical synthesis of molecular, tissue and biomechanical processes related to the pathogenesis, prevention and treatment of bone and joint diseases; (2) develop a dialogue between basic and clinical investigators; (3) provide training workshops for junior faculty and students that help bridge the gaps between disciplines; (4) provide a forum for student training and the opportunity for junior investigators o talk with more senior scientists in a small group setting. A new partnership between the Workshop and the Orthopaedic Research Society (ORS) provides maximum visibility through broadcast emails and links on the ORS website. In celebration of the 50th year since the first Workshop in 1965, and its founder's (W.S.S. Jee) 90th birthday, the Workshop will address the theme of New Mechanisms for Old Problem, bringing new data to topics that were originally developed at the Workshop. This includes: Cell Signaling and the Coupling of Bone Resorption and Formation; The Role of Cortical Porosity in Skeletal Fragility, and Perilacunar Remodeling. To this will be added two very innovative new topics: Using Bioimaging and 3D Printing to Regenerate Musculoskeletal Tissue and Bone and Joint Pain. Many opportunities are provided for junior investigators to interact with more senior investigators. A Career Development Workshop specifically geared toward young investigators will be held during one afternoon. Nine ASBMR/Harold M. Frost Young Investigator Awardees will present their work from the podium, and ten Alice Jee Young Investigator Awardees will present posters. Six Awards are given to investigators from under- represented minorities. The Sunday evening session is set aside for a Plenary Lecture, followed by a Poster Session highlighting submitted abstracts. A summary of the workshop will be provided through the Journal of Orthopaedic Research. Performance Site Sun Valley, Idaho Key Personnel Name Organization Burr, David B. Indiana University Bellido, Teresita Indiana University Alex Robling Indiana University Role on Project Director, PI Associate Director, Co-I Associate Director, Co-I