1. Department of Cell Biology, University of Massachusetts Medical School, Worcester, MA, USA
2. Heisenberg-Group for Molecular Skeletal Biology, Department of Trauma, Hand & Reconstructive Surgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
3. Department of Biochemistry & Cancer Center, University of Vermont College of Medicine, Burlington, VT, USA
4. Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
5. Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA