The CAGE complex: a hollow, megadalton, protein assembly in prokaryotic and eukaryotic microbes.

ABSTRACT: We describe the identification and three-dimensional (3D) structure determination of an approx. 1 MDa, hollow, elliptical protein cage discovered while surveying proteins isolated from the ciliary matrix of the ciliate Tetrahymena thermophila. By using mass spectrometry, AlphaFold, and cryo-electron microscopy, we identified the cage-like protein and determined its stoichiometry, mid-resolution 3D structure, and protein interactions. A sequence survey revealed several thousand homologs, with conservation across eukaryotic microbes spanning green algae, fungi, amoebozoans, choanoflagellates, and SAR organisms, as well as deep homology to genes in gram-negative predominantly marine prokaryotes and microbial mats, implying an ancient origin and arguing against a eukaryote-specific func

SUBMITTER: McCafferty CL 

PROVIDER: S-EPMC12485934 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature