Structural insights into the human PA28-20S proteasome enabled by efficient tagging and purification of endogenous proteins.
Proc Natl Acad Sci U S A
; 119(33): e2207200119, 2022 08 16.
Article
en En
| MEDLINE
| ID: mdl-35858375
ABSTRACT
The ability to produce folded and functional proteins is a necessity for structural biology and many other biological sciences. This task is particularly challenging for numerous biomedically important targets in human cells, including membrane proteins and large macromolecular assemblies, hampering mechanistic studies and drug development efforts. Here we describe a method combining CRISPR-Cas gene editing and fluorescence-activated cell sorting to rapidly tag and purify endogenous proteins in HEK cells for structural characterization. We applied this approach to study the human proteasome from HEK cells and rapidly determined cryogenic electron microscopy structures of major proteasomal complexes, including a high-resolution structure of intact human PA28αß-20S. Our structures reveal that PA28 with a subunit stoichiometry of 3α/4ß engages tightly with the 20S proteasome. Addition of a hydrophilic peptide shows that polypeptides entering through PA28 are held in the antechamber of 20S prior to degradation in the proteolytic chamber. This study provides critical insights into an important proteasome complex and demonstrates key methodologies for the tagging of proteins from endogenous sources.
Palabras clave
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Complejo de la Endopetidasa Proteasomal
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Citometría de Flujo
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Edición Génica
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Proteínas Musculares
Límite:
Humans
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Año:
2022
Tipo del documento:
Article