TULA (T cell ubiquitin ligand), also known as UBASH3A (ubiquitin associated and SH3 domain containing A), STS-2 or CLIP4, is a 661 amino acid protein that localizes to both the nucleus and the cytoplasm and contains one SH3 domain and one UBA domain. Expressed at high levels in thymus, bone marrow, spleen and peripheral blood leukocytes, TULA exists as either a homodimer or a homo-oligomer that interferes with the degradation of receptor-type tyrosine kinases and promotes the accumulation of activated receptors on the cell surface. Additionally, TULA is part of an EGFR- and Cbl-containing complex that interacts with ubiquitinated proteins. The gene encoding TULA, which maps to human chromosome 21, may be involved in the pathogenesis of type I diabetes. Multiple isoforms of TULA are produced due to alternative splicing events.