A cationic motif upstream Engrailed2 homeodomain controls cell internalization through selective interaction with heparan sulfates

Sébastien Cardon (1) , Yadira Hervis (1) , Gérard Bolbach (1, 2) , Chrystel Lopin-Bon (3) , Jean-Claude Jacquinet (3) , Françoise Illien (1, 4) , Astrid Walrant (1, 4) , Delphine Ravault (1, 4) , Bingwei He (1) , Laura Molina (5, 1) , Fabienne Burlina (1) , Olivier Lequin (1) , Alain Joliot (6, 7) , Ludovic Carlier (8, 1) , Sandrine Sagan (1)

1 LBM UMR 7203 - Laboratoire des biomolécules
2 MS3U - Spectrométrie de masse de Sorbonne Université [IBPS]
3 ICOA - Institut de Chimie Organique et Analytique
4 LBM-E2 - Analyse, Interactions Moléculaires et Cellulaires
5 AMU SMPM MED - Aix-Marseille Université - École de médecine
6 INSERM - Institut National de la Santé et de la Recherche Médicale
7 Centre de recherche de l'Institut Curie [Paris]
8 LBM-E3 - Structure et Dynamique des Biomolécules

Engrailed2 (En2) is a transcription factor that transfers from cell to cell through unconventional pathways. The poorly understood internalization mechanism of this cationic protein is proposed to require an initial interaction with cell-surface glycosaminoglycans (GAGs). To decipher the role of GAGs in En2 internalization, we have quantified the entry of its homeodomain region in model cells that differ in their content in cell-surface GAGs. The binding specificity to GAGs and the influence of this interaction on the structure and dynamics of En2 was also investigated at the amino acid level. Our results show that a high-affinity GAG-binding sequence (RKPKKKNPNKEDKRPR), upstream of the homeodomain, controls En2 internalization through selective interactions with highly-sulfated heparan sulfate GAGs. Our data underline the functional importance of the intrinsically disordered basic region upstream of En2 internalization domain, and demonstrate the critical role of GAGs as an entry gate, finely tuning homeoprotein capacity to internalize into cells.

Domains: Genomics [q-bio.GN]

Sébastien Cardon, Yadira Hervis, Gérard Bolbach, Chrystel Lopin-Bon, Jean-Claude Jacquinet, et al.. A cationic motif upstream Engrailed2 homeodomain controls cell internalization through selective interaction with heparan sulfates. Nature Communications, 2023, 14 (1), pp.1998. ⟨10.1038/s41467-023-37757-6⟩. ⟨hal-04263695⟩