Year: 2003
Type: article
Abstract: Ubiquitin-protein ligases (E3s) of the HECT family share a conserved catalytic region that is homologous to the E6-AP C terminus. The HECT domain defines a large E3 family, but only a handful of these enzymes have been defined with respect to substrate specificity or biological function. We showed previously that the C-terminal domain of one family member, KIAA10, catalyzes the assembly of polyubiquitin chains, whereas the N-terminal domain binds to proteasomes in vitro (You, J., and Pickart, C. M. (2001) J. Biol. Chem. 276, 19871-19878). We show here that KIAA10 also associates with proteasomes within cells but that this association probably involves additional contacts with proteasome subunits other than the one (S2/Rpn1) identified in our previous work. We report that the N-domain of KIAA10 also mediates an association with TIP120B (TATA-binding protein-interacting protein 120B), a putative transcriptional regulator. Biochemical and co-transfection studies revealed that TIP120B, but not the closely related protein TIP120A, is a specific substrate of KIAA10 in vitro and within C2C12 myoblasts but not in Cos-1 cells. KIAA10 and TIP120B are both highly expressed in human skeletal muscle, suggesting that KIAA10 may regulate TIP120B homeostasis specifically in this tissue.
Source: Journal of Biological Chemistry
Authors: Jianxin You, Min Wang, Tsutomu Aoki, Taka-aki Tamura, Cecile M. Pickart
Institutions: Johns Hopkins University, Chiba University
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
OpenAlex ID: W2136406488