RTKs, such as EGFR, HER2, MET and RET, are often inappropriately active (due to mutation or overexpression) in a wide array of epithelial malignancies. My laboratory cloned two of the three members of the mammalian Cbl protein family and demonstrated that they are negative regulators of the EGFR in mammalian cells. We have shown that Cbl proteins are RING finger E3s and that all mammalian Cbl proteins mediate ubiquitination of the activated EGFR, resulting in the degradation of the activated EGFR signaling complex. Work in my lab, in collaborations with other laboratories, and by other investigators has shown the Cbl proteins regulate many RTKs and signaling pathways. In addition, my lab has contributed to the structure function analysis of the Cbl proteins. More recently my laboratory has identified and characterized proteins which interact with and modify the function of Cblc, the least well characterized Cbl protein, identified and are characterizing E2 proteins that interact with the Cbl proteins, and identified mutant forms of Cbl proteins in human and mouse epithelial tumors. Ongoing work: 1) investigates the spectrum of ubiquitin conjugating enzymes (E2s) that function with Cbl protiens. 2) investigates the proteins that collaborate with Cbl proteins to mediate RTK downregulation by identifying proteins in the active complex by mass spec analysis. 3) studies mutations of Cbl protiens found in murine and human solid tumors. 4) developes a screen to identify Cbl E3 inhibitors

National Institute of Health (NIH)
National Cancer Institute (NCI)
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Basic Sciences
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Schardt, John S; Oubaid, Jinan M; Williams, Sonya C et al. (2017) Engineered Multivalency Enhances Affibody-Based HER3 Inhibition and Downregulation in Cancer Cells. Mol Pharm 14:1047-1056
Li, Minghui; Kales, Stephen C; Ma, Ke et al. (2016) Balancing Protein Stability and Activity in Cancer: A New Approach for Identifying Driver Mutations Affecting CBL Ubiquitin Ligase Activation. Cancer Res 76:561-71
Liyasova, Mariya S; Ma, Ke; Lipkowitz, Stanley (2015) Molecular pathways: cbl proteins in tumorigenesis and antitumor immunity-opportunities for cancer treatment. Clin Cancer Res 21:1789-94
Qiao, Guilin; Ying, Haiyan; Zhao, Yixia et al. (2014) E3 ubiquitin ligase Cbl-b suppresses proallergic T cell development and allergic airway inflammation. Cell Rep 6:709-23
Veselits, Margaret; Tanaka, Azusa; Lipkowitz, Stanley et al. (2014) Recruitment of Cbl-b to B cell antigen receptor couples antigen recognition to Toll-like receptor 9 activation in late endosomes. PLoS One 9:e89792
Ryan, Philip E; Kales, Stephen C; Yadavalli, Rajgopal et al. (2012) Cbl-c ubiquitin ligase activity is increased via the interaction of its RING finger domain with a LIM domain of the paxillin homolog, Hic 5. PLoS One 7:e49428
Kales, Stephen C; Ryan, Philip E; Lipkowitz, Stanley (2012) Cbl exposes its RING finger. Nat Struct Mol Biol 19:131-3
Guo, Hui; Qiao, Guilin; Ying, Haiyan et al. (2012) E3 ubiquitin ligase Cbl-b regulates Pten via Nedd4 in T cells independently of its ubiquitin ligase activity. Cell Rep 1:472-82
Lipkowitz, Stanley; Weissman, Allan M (2011) RINGs of good and evil: RING finger ubiquitin ligases at the crossroads of tumour suppression and oncogenesis. Nat Rev Cancer 11:629-43
Yoon, Hye-Young; Kales, Stephen C; Luo, Ruibai et al. (2011) ARAP1 association with CIN85 affects epidermal growth factor receptor endocytic trafficking. Biol Cell 103:171-84

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