PTMScan ® Ubiquitin Remnant Motif (K-epsilon-GG) Kit

Ubiquitin is a conserved polypeptide unit that plays an important role in the ubiquitin-proteasome pathway. Ubiquitin can be covalently linked to many cellular proteins by the ubiquitination process, which targets proteins for degradation by the 26S proteasome. Three components are involved in the target protein-ubiquitin conjugation process. Ubiquitin is first activated by forming a thiolester complex with the activation component E1; the activated ubiquitin is subsequently transferred to the ubiquitin-carrier protein E2, then from E2 to ubiquitin ligase E3 for final delivery to the epsilon-NH2 of the target protein lysine residue (2-4). The ubiquitin-proteasome pathway has been implicated in a wide range of normal biological processes and in disease-related abnormalities. Several proteins such as IκB, p53, cdc25a and bcl-2 have been shown to be targets for the ubiquitin-proteasome process as part of regulation of cell cycle progression, differentiation, cell stress response, and apoptosis (5-8).In this assay, the PTMScan® Ubiquitin Remnant Motif (K-ε-GG) Antibody Bead Conjugate, a proprietary ubiquitin branch (“K-ε-GG”) antibody with specificity for a di-glycine tag that is the remnant of ubiqui- tin left on protein substrates after trypsin digestion, is used to enrich ubiquitinated peptides from trypsin digested cell samples. This enrichment is followed by LC-MS/MS analy- sis for quantitative profiles of hundreds to over a thousand non-redundant ubiquitinated sequences. 1.Rush, J. et al. (2005) Nat Biotechnol 23, 94-101. 2.Ciechanover, A. (1998) EMBO J 17, 7151-60. 3.Hochstrasser, M. (2000) Nat Cell Biol 2, E153-7. 4.Hochstrasser, M. (2000) Science 289, 563-4. 5.Bernardi, R. et al. (2000) Oncogene 19, 2447-54. 6.Aberle, H. et al. (1997) EMBO J 16, 3797-804. 7.Salomoni, P. and Pandolfi, P.P. (2002) Nat Cell Biol 4, E152-3. 8.Jesenberger, V. and Jentsch, S. (2002) Nat Rev Mol Cell Biol 3, 112-21.