Ubiquitin Associated And SH3 Domain Containing Protein A (UBASH3A)

The deduced 661-amino acid UBASH3A protein contains a ubiquitin-associated (UBA) domain, an SH3 domain, and a novel domain, designated HCD, that shows homology to hypothetical proteins from C. elegans and Drosophila. The HCD domain contains a strong potential nuclear localization signal. The authors stated that this was the first reported protein containing both UBA and SH3 domains. They found the highest expression of UBASH3A in tissues belonging to the immune system, including spleen, peripheral blood leukocytes, and bone marrow.

Northern and Western blot analyses showed that expression of Sts1 was ubiquitous, whereas expression of Sts2 was restricted to T cells in thymus, spleen, and bone marrow.