Negative regulation of Lck by Cbl ubiquitin ligase

Navin Rao, Sachiko Miyake, Alagarsamy Lakku Reddi, Patrice Douillard, Amiya K. Ghosh, Ingrid L. Dodge, Pengcheng Zhou, Norvin D. Fernandes, Hamid Band

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100 Scopus citations

Abstract

The Cbl-family ubiquitin ligases function as negative regulators of activated receptor tyrosine kinases by facilitating their ubiquitination and subsequent targeting to lysosomes. Cbl associates with the lymphoid-restricted nonreceptor tyrosine kinase Lck, but the functional relevance of this interaction remains unknown. Here, we demonstrate that T cell receptor and CD4 coligation on human T cells results in enhanced association between Cbl and Lck, together with Lck ubiquitination and degradation. A Cbl-/- T cell line showed a marked deficiency in Lck ubiquitination and increased levels of kinase-active Lck. Coexpression in 293T cells demonstrated that Lck kinase activity and Cbl ubiquitin ligase activity were essential for Lck ubiquitination and negative regulation of Lck-dependent serum response element-luciferase reporter activity. The Lck SH3 domain was pivotal for Cbl-Lck association and Cbl-mediated Lck degradation, with a smaller role for interactions mediated by the Cbl tyrosine kinase-binding domain. Finally, analysis of a ZAP-70-deficient T cell line revealed that Cbl inhibited Lck-dependent mitogen-activated protein kinase activation, and an intact Cbl RING finger domain was required for this functional effect. Our results demonstrate a direct, ubiquitination-dependent, negative regulatory role of Cbl for Lck in T cells, independent of Cbl-mediated regulation of ZAP-70.

Original languageEnglish (US)
Pages (from-to)3794-3799
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume99
Issue number6
DOIs
StatePublished - Mar 19 2002

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Rao, N., Miyake, S., Reddi, A. L., Douillard, P., Ghosh, A. K., Dodge, I. L., Zhou, P., Fernandes, N. D., & Band, H. (2002). Negative regulation of Lck by Cbl ubiquitin ligase. Proceedings of the National Academy of Sciences of the United States of America, 99(6), 3794-3799. https://doi.org/10.1073/pnas.062055999