Drebrin Like Protein (DBNL)

The predicted 430-amino acid protein has a calculated molecular mass of 48 kD. The N terminus of HIP55 contains a putative actin-binding domain found in drebrins, which are involved in brain development, and the C terminus contains an SH3 domain. Western blot analysis detected a 55-kD protein. Northern blot analysis revealed ubiquitous expression of a 2.3-kb transcript, with highest levels in spleen and peripheral blood leukocytes.

HIP55 did not contribute to early formation of T cell-antigen-presenting cell (APC) conjugates. However, they identified HIP55 as a key constituent of the immunologic synapse, regulating T-cell activation by bridging T-cell receptors and the actin cytoskeleton to gene activation and endocytic processes.