EMD-26624
Composite cryo-EM density map of the 48-nm repeat of the human respiratory doublet microtubule
EMD-26624
Single-particle3.6 Å
Deposition: 11/04/2022
Map released: 05/10/2022
Last modified: 12/06/2024
Sample Organism:
Homo sapiens
Sample: Doublet microtubule and associated proteins
Fitted models: 7ung
Deposition Authors: Gui M , Croft JT , Zabeo D , Acharya V, Kollman JM, Burgoyne T , Hoog JL , Brown A
Sample: Doublet microtubule and associated proteins
Fitted models: 7ung
Deposition Authors: Gui M , Croft JT , Zabeo D , Acharya V, Kollman JM, Burgoyne T , Hoog JL , Brown A
SPACA9 is a lumenal protein of human ciliary singlet and doublet microtubules.
Gui M ,
Croft JT ,
Zabeo D ,
Acharya V,
Kollman JM,
Burgoyne T ,
Hoog JL ,
Brown A
(2022) PNAS , 119 , e2207605119 - e2207605119
(2022) PNAS , 119 , e2207605119 - e2207605119
Abstract:
The cilium-centrosome complex contains triplet, doublet, and singlet microtubules. The lumenal surfaces of each microtubule within this diverse array are decorated by microtubule inner proteins (MIPs). Here, we used single-particle cryo-electron microscopy methods to build atomic models of two types of human ciliary microtubule: the doublet microtubules of multiciliated respiratory cells and the distal singlet microtubules of monoflagellated human spermatozoa. We discover that SPACA9 is a polyspecific MIP capable of binding both microtubule types. SPACA9 forms intralumenal striations in the B tubule of respiratory doublet microtubules and noncontinuous spirals in sperm singlet microtubules. By acquiring new and reanalyzing previous cryo-electron tomography data, we show that SPACA9-like intralumenal striations are common features of different microtubule types in animal cilia. Our structures provide detailed references to help rationalize ciliopathy-causing mutations and position cryo-EM as a tool for the analysis of samples obtained directly from ciliopathy patients.
The cilium-centrosome complex contains triplet, doublet, and singlet microtubules. The lumenal surfaces of each microtubule within this diverse array are decorated by microtubule inner proteins (MIPs). Here, we used single-particle cryo-electron microscopy methods to build atomic models of two types of human ciliary microtubule: the doublet microtubules of multiciliated respiratory cells and the distal singlet microtubules of monoflagellated human spermatozoa. We discover that SPACA9 is a polyspecific MIP capable of binding both microtubule types. SPACA9 forms intralumenal striations in the B tubule of respiratory doublet microtubules and noncontinuous spirals in sperm singlet microtubules. By acquiring new and reanalyzing previous cryo-electron tomography data, we show that SPACA9-like intralumenal striations are common features of different microtubule types in animal cilia. Our structures provide detailed references to help rationalize ciliopathy-causing mutations and position cryo-EM as a tool for the analysis of samples obtained directly from ciliopathy patients.