A dual role of EGFR protein tyrosine kinase signaling in ubiquitination of AAV2 capsids and viral second-strand DNA synthesis

作者：Zhong, Li; Zhao, Weihong; Wu, Jianqing; Li, Baozheng; Zolotukhin, Sergei; Govindasamy, Lakshmanan; Agbandje-McKenna, Mavis; Srivastava, Arun^*

来源：Molecular Therapy, 2007, 15(7): 1323-1330.

DOI：10.1038/sj.mt.6300170

• ADENOASSOCIATED VIRUS TYPE-2
• 2-MEDIATED GENE-TRANSFER
• GROWTH-FACTOR RECEPTOR
• CELLULAR FKBP52 PROTEIN
• B-ALPHA PROTEOLYSIS
• RATE-LIMITING STEP
• VECTORS IN-VITRO
• TRANSGENE EXPRESSION
• INTRACELLULAR TRAFFICKING
• EFFICIENT TRANSDUCTION

A 52 kd cellular protein, FK506-binding protein (FKBP52), phosphorylated at tyrosine residues by epidermal growth factor receptor protein tyrosine kinase (EGFR-PTK), inhibits adeno-associated virus 2 (AAV2) second-strand DNA synthesis and transgene expression. FKBP52 is dephosphorylated at tyrosine residues by T-cell protein tyrosine phosphatase (TC-PTP), and TC-PTP over-expression leads to improved viral second-strand DNA synthesis and improved transgene expression. In these studies, we observed that perturbation of EGFR-PTK signaling by a specific inhibitor, Tyrphostin 23 (Tyr23), augmented the transduction efficiency of the single-stranded AAV (ssAAV) vector as well as the self-complementary AAV (scAAV) vector. Similarly, tyrosine-dephosphorylation of FKBP52 by TC-PTP resulted in increased transduction by both vectors. These data suggested that EGFR-PTK signaling also affects aspects of AAV transduction other than viral second-strand DNA synthesis. We document that inhibition of EGFR-PTK signaling leads to decreased ubiquitination of AAV2 capsids which, in turn, facilitates nuclear transport by limiting proteasome-mediated degradation of AAV vectors. We also document that Tyr23-mediated increase in AAV2 transduction efficiency is not further enhanced by a specific proteasome inhibitor, MG132. Thus, EGFR-PTK signaling modulates ubiquitin (Ub)/proteasome pathway-mediated intracellular trafficking as well as FKBP52-mediated second-strand DNA synthesis of AAV2 vectors. This has implications in the optimal use of AAV vectors in gene therapy.

• 出版日期2007-7
• 单位南京医科大学