The cytoskeleton of a red blood cell (RBC) is anchored to the cell membrane by the ankyrin complex. This complex is assembled during RBC genesis and comprises primarily band 3, protein 4.2 and ankyrin, whose mutations contribute to numerous human inherited diseases. High-resolution structures of the ankyrin complex have been long sought-after to understand its assembly and disease-causing mutations. Here, we analyzed native complexes on the human RBC membrane by stepwise fractionation. Cryo-electron microscopy structures of nine band-3-associated complexes reveal that protein 4.2 stabilizes the cytoplasmic domain of band 3 dimer. In turn, the superhelix-shaped ankyrin binds to this protein 4.2 via ankyrin repeats (ARs) 6-13 and to another band 3 dimer via ARs 17-20, bridging two band 3 dimers in the ankyrin complex. Integration of these structures with both prior data and our biochemical data supports a model of ankyrin complex assembly during erythropoiesis and identifies interactions essential for the mechanical stability of RBC.
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http://dx.doi.org/10.1038/s41594-022-00779-7 | DOI Listing |
Nat Struct Mol Biol
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Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Frankfurt, Germany.
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Department of Cardiology, Pulmonology, and Nephrology Yamagata University School of Medicine Yamagata Japan.
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Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Frankfurt, Germany.
The concept of Targeted Protein Degradation (TPD) has been introduced as an attractive alternative to the development of classical inhibitors. TPD can extend the range of proteins that can be pharmacologically targeted beyond the classical targets for small molecule inhibitors, as a binding pocket is required but its occupancy does not need to lead to inhibition. The method is based on either small molecules that simultaneously bind to a protein of interest and to a cellular E3 ligase and bring them in close proximity (molecular glue) or a bi-functional molecule synthesized from the chemical linkage of a target protein-specific small molecule and one that binds to an E3 ligase (Proteolysis Targeting Chimeras (PROTAC)).
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View Article and Find Full Text PDFJ Mol Biol
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Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK; Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge CB2 0AW, UK. Electronic address:
The Human Silencing Hub (HUSH) guards the genome from the pathogenic effects of retroelement expression. Composed of MPP8, TASOR, and Periphilin-1, HUSH recognizes actively transcribed retrotransposed sequences by the presence of long (>1.5-kb) nascent transcripts without introns.
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