GPRC5A regulates keratinocyte adhesion and migration through nuclear translocation of its C-terminus region
G-Protein Coupled Receptor, Class C, Group 5, Member A (GPRC5A) is well-documented in lung and various epithelial cancers. However, its role in the skin remains unexplored. In this study, we investigated the function of this receptor in skin biology and our research demonstrated that its expression responds to mechanical substrate changes in human primary keratinocytes. Furthermore, we observed GPRC5A reinduction during wound healing at the leading edges in an ex vivo burn model, coinciding with the translocation of its C-terminal region into the nucleus. We identified the cleavage site of GPRC5A by N-TAILS analysis, and cathepsin G was characterized as responsible for proteolysis in cultured cells.  To gain a deeper understanding of GPRC5A's role in keratinocyte, we performed GPRC5A knockdown in N/TERT-1 cells using short-hairpin RNA. Our findings strongly suggest a close association between GPRC5A and adhesion regulation pathways, but also demonstrate that GPRC5AKD enhanced cell adhesion while reducing cell migration and differentiation. Importantly, these effects were reversed by adding a recombinant polypeptide mimicking the C-terminal region of GPRC5A.  Overall, our study reveals an unexpected role of GPRC5A in regulating keratinocyte behavior, implicating its C-terminal region translocation into the nucleus. These results open up interesting strategic pathways for wound healing. Overall design: In order to identify novel mechanosensitive elements from epidermal cells, primary human keratinocytes were isolated from 3 different individuals and subjected to cell culture on substrates of different stiffness prior to total RNA extraction. We compared the transcriptomic profiles of cells grown for 72 h on glass coverslips (glass) or on 4kPa hydrogels (soft), or after transplanting the cells from hydrogel to plastic support for 24 h (soft.glass).