Summary
An important step in the ubiquitin proteolytic cascade is specific recognition of the substrate by a member of the ubiquitin ligases family of proteins—an E3, that is followed by generation of the polyubiquitin degradation signal. For most substrates, it is believed, though it has been demonstrated experimentally only for a few, that the first ubiquitin moiety is conjugated, via its C-terminal Gly76 residue, to an ε-NH2 group of an internal Lys residue. Recent findings indicate that for several proteins, the first ubiquitin moiety is fused linearly to the α-NH2 group of the N-terminal residue. Important biological questions relate (1) to the evolutionary requirement for an alternative mode of ubiquitination, (2) to the identity of the set of proteins in the proteome that undergoes N-terminal ubiquitination, and (3) to the relationship between N-terminal ubiquitination and N-terminal acetylation. In this chapter we describe methods that will enable researchers to identify this novel mode of ubiquitination.
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Acknowledgments
Research in the laboratory of A.C. is supported by grants from Prostate Cancer Foundation (PCF) Israel-Centers of Excellence Program, the Israel Science Foundation-Centers of Excellence Program, a Professorship funded by the Israel Cancer Research Fund, ICRF (USA), and the Foundation for Promotion of Research in the Technion. Infrastructural equipment has been purchased with the support of the Wolfson Charitable Fund, Center of Excellence for studies on Turnover of Cellular Proteins and its Implications to Human Diseases.
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Ciechanover, A. (2005). N-Terminal Ubiquitination. In: Patterson, C., Cyr, D.M. (eds) Ubiquitin-Proteasome Protocols. Methods in Molecular Biology™, vol 301. Humana Press. https://doi.org/10.1385/1-59259-895-1:255
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DOI: https://doi.org/10.1385/1-59259-895-1:255
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