We would like to highlight another new reagent and protocol for intracellular delivery of ubiquitin(-like) reagents (Figure 1) based on work by Giancola et al. from the lab of Prof. Ronald T. Raines. 

Here endosomolytic peptide L17ER4 (UbiQ-381) does not only provide cytosolic access to ubiquitin(-like) reagents but also allows functional incorporation of ubiquitin into endogenous proteins (Figure 1).

In our protocol P011, we outline the application of UbiQ-381 in live cell experiments with ubiquitin(-like) reagents, as decribed by Giancola et al..

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Figure 1 – using UbiQ-381 for uptake and functional incorporation of ubiquitin into live human cells.

Reference: Giancola et al. Cytosolic Delivery of Functional Ubiquitin, J Pept Sci 2025, 31, e70026.