# First Steps toward the Design of Peptides that Influence the Intracellular Palmitoylation Machinery

## TL;DR

Researchers designed cell-permeable peptides to influence protein palmitoylation, a key process in cancer and other diseases, and found one peptide, DC-2, that alters cancer-related proteins.

## Contribution

The study introduces cell-permeable DHHC peptides as a novel tool to modulate intracellular palmitoylation and cancer-related signaling.

## Key findings

- DC-2 peptides internalize efficiently into multiple cell lines and human breast cell spheroids.
- DC-2 alters the localization of HRas and affects signaling of the epidermal growth factor receptor.
- DC peptides show cytotoxic effects against cancerous cells and impact palmitoylated proteins.

## Abstract

Protein S‐palmitoylation is a reversible posttranslational modification transferring the 16‐carbon fatty acid palmitate to cysteines. It plays a critical role in many cellular processes by influencing protein function, localization, stability, and protein–protein interactions and has a significant impact on various physiological and pathological conditions. This emphasizes the need to develop new technologies to study and treat diseases associated with aberrant palmitoylation. To address these challenges, cell‐permeable peptides containing an Asp–His–His–Cys (DHHC) palmitoylation motif are presented aiming to affect intracellular protein S‐palmitoylation. A small library of peptides is generated and screened for cellular uptake and cell compatibility. Interestingly, the newly designed peptides internalize to high extent into different cell lines and human breast cell spheroids dependent on their palmitoylation motif. In addition, out of this screen, DC‐2 is identified as very potent and this peptide is investigated in more detail concerning its impact on palmitoylated proteins that are connected to cancer progression. These initial explorations highlight that DC‐2 affected the localization of HRas and altered S‐palmitoylation‐related signaling cascades of epidermal growth factor receptor. These findings suggest a peptide‐driven impact on proteins having palmitoylation sites and highlight cell‐permeable DHHC peptides as a potential tool to be further evolved in the context of palmitoylation and cancer.

Herein, DC peptides consisting of the cell‐penetrating peptide sC18* and a Asp–His–His–Cys (DHHC) motif derived from human ZDHHC palmitoyltransferase are highlighted. DC peptides demonstrate high cellular internalization into various cellular models, exert cytotoxic effects against cancerous cells, and alter the function and localization of known palmitoylation substrate proteins.© 2025 WILEY‐VCH GmbH