Palmitoylation of MPP1 (Membrane-palmitoylated Protein 1)/p55 Is Crucial for Lateral Membrane Organization in Erythroid Cells

Agnieszka Łach,Michał Grzybek,Elżbieta Heger,Justyna Korycka,Marcin Wolny,Jakub Kubiak,Adam Kolondra,Dżamila M Bogusławska,Katarzyna Augoff,Michał Majkowski,Joanna Podkalicka,Jakub Kaczor,Adam Stefanko,Kazimierz Kuliczkowski,Aleksander F Sikorski

doi:10.1074/jbc.m111.332981

Abstract

S-Acylation of proteins is a ubiquitous post-translational modification and a common signal for membrane association. The major palmitoylated protein in erythrocytes is MPP1, a member of the MAGUK family and an important component of the ternary complex that attaches the spectrin-based skeleton to the plasma membrane. Here we show that DHHC17 is the only acyltransferase present in red blood cells (RBC). Moreover, we give evidence that protein palmitoylation is essential for membrane organization and is crucial for proper RBC morphology, and that the effect is specific for MPP1. Our observations are based on the clinical cases of two related patients whose RBC had no palmitoylation activity, caused by a lack of DHHC17 in the membrane, which resulted in a strong decrease of the amount of detergent-resistant membrane (DRM) material. We confirmed that this loss of detergent-resistant membrane was due to the lack of palmitoylation by treatment of healthy RBC with 2-bromopalmitic acid (2-BrP, common palmitoylation inhibitor). Concomitantly, fluorescence lifetime imaging microscopy (FLIM) analyses of an order-sensing dye revealed a reduction of membrane order after chemical inhibition of palmitoylation in erythrocytes. These data point to a pathophysiological relationship between the loss of MPP1-directed palmitoylation activity and perturbed lateral membrane organization.

Highlights

Lateral membrane organization is important in many essential cellular functions
Unknown Hemolytic Anemia Is Caused by Loss of Protein Palmitoylation Activity—During our studies on hereditary spherocytosis, we identified a family in which 2 members displayed symptoms of hemolytic
As the ZDHHC17 message was detected in reticulocytes from the patients (Fig. 1B), we hypothesize that the molecular basis for the anemia involves regulation of translation, sorting, or integrating the protein into the membrane during biosynthesis

Summary

Introduction

Lateral membrane organization is important in many essential cellular functions. Results: Lack of palmitoylation of normal or unknown anemia erythrocyte membrane proteins, MPP1, leads to changes in lateral membrane organization. Conclusion: Palmitoylation of MPP1 is crucial for membrane organization and is linked to the pathogenesis of hemolytic anemia. Significance: This might be the first mechanism of biological control of membrane lateral organization. S-Acylation of proTtehiniss aisrtaiculebiqhuaitsoubsepeonstw-triatnhsdlartaiownanl bythtehmeeamubtrhanoer,swfhoilclhowreisnugltecdoinncaersntrsong decrease of the modification and aracoismemdoanbsiogunatl dfoartmaeimntberagnreitayssioncisatuiopnp.

Results

Discussion

Conclusion