Leupaxin, which belongs to the paxillin extended family of adaptor proteins, was previously identified as a component of the sealing zone in osteoclasts. Leupaxin was found to associate with several podosomal proteins, such as the protein tyrosine kinase Pyk2, the protein-tyrosine phosphatase-PEST (PTP-PEST), actin-binding proteins, and regulators of actin cytoskeletal reorganization. It was previously demonstrated that inhibition of leupaxin expression resulted in reduced osteoclast-mediated resorption. In the current study, overexpression of leupaxin in murine osteoclasts resulted in both enhanced resorptive activity and cell adhesion, as assessed by in vitro resorption assays. The overexpression of LPXN resulted in an increased association of Pyk2 with LPXN. In an attempt to determine an additional biochemical basis for the observed phenomenon in increased osteoclast activity, a co-immunoprecipitation screen for additional binding partners revealed that Src, a protein tyrosine kinase that is critical to both podosome formation and osteoclast function, was also associated with leupaxin. After exposure to the pro-inflammatory and osteoclastogenic cytokine TNF-, there was an increase in the level of Src that coimmunoprecipitated with leupaxin. Our data indicate that association of the scaffold protein leupaxin with Src adds further complexity to the organization of the podosomal signaling complex in osteoclasts.