Bridging Integrator 2 (BIN2)

BIN2 has acidic and serine/proline-rich stretches but lacks a C-terminal SH3 domain or a MYC-interacting region. Northern blot analysis revealed expression of a major 2.6-kb transcript that was highest in spleen and peripheral blood leukocytes and also high in thymus, colon, and placenta, suggesting preferential expression in hematopoietic tissues. Strong expression was detected in lymphoid and granulocytic cell lines but not other cell lines. Coimmunoprecipitation and Western blot analyses showed expression of an 80-kD protein that interacts with the N-terminal portion of the BAR domain of BIN1 isoforms but not with AMPH. Immunofluorescence microscopy demonstrated cytosolic expression and lack of receptor-mediated endocytic function for BIN2. Functional analysis showed that BIN2 lacks tumor suppressor features.