Production of Osteoclasts for Studying Protein Tyrosine Phosphatase Signaling

Osteoclasts, specialized cells that degrade bone, are key components of the cellular system that regulates and maintains bone homeostasis. Aberrant function of osteoclasts can lead to pathological loss or gain of bone mass, such as in osteopetrosis, osteoporosis, and several types of cancer that metastasize to bone. Phosphorylation of osteoclast proteins on tyrosine residues is critical for formation of osteoclasts and for their proper function and responses to physiological signals. Here we describe preparation and growth of osteoclasts from bone marrow of mice, use of viral vectors to downregulate expression of endogenous proteins and to express exogenous proteins in osteoclasts, and analysis of signaling processes triggered by M-CSF, estrogen, and physical contact with matrix in these cells.