This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.

Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.

8ou0

From Proteopedia

Jump to: navigation, search

bovine sperm endpiece singlet microtubules (one tubulin dimer and associated microtubule inner proteins)

Structural highlights

8ou0 is a 4 chain structure with sequence from Bos taurus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Electron Microscopy, Resolution 3.5Å
Ligands:	, ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

TBB4B_BOVIN Tubulin is the major constituent of microtubules, a cylinder consisting of laterally associated linear protofilaments composed of alpha- and beta-tubulin heterodimers (PubMed:6504138, PubMed:2207090, PubMed:7704569). Microtubules grow by the addition of GTP-tubulin dimers to the microtubule end, where a stabilizing cap forms. Below the cap, tubulin dimers are in GDP-bound state, owing to GTPase activity of alpha-tubulin (PubMed:6504138, PubMed:2207090, PubMed:7704569).^[1] ^[2] ^[3]

Publication Abstract from PubMed

Sperm motility is crucial to reproductive success in sexually reproducing organisms. Impaired sperm movement causes male infertility, which is increasing globally. Sperm are powered by a microtubule-based molecular machine-the axoneme-but it is unclear how axonemal microtubules are ornamented to support motility in diverse fertilization environments. Here, we present high-resolution structures of native axonemal doublet microtubules (DMTs) from sea urchin and bovine sperm, representing external and internal fertilizers. We identify >60 proteins decorating sperm DMTs; at least 15 are sperm associated and 16 are linked to infertility. By comparing DMTs across species and cell types, we define core microtubule inner proteins (MIPs) and analyze evolution of the tektin bundle. We identify conserved axonemal microtubule-associated proteins (MAPs) with unique tubulin-binding modes. Additionally, we identify a testis-specific serine/threonine kinase that links DMTs to outer dense fibers in mammalian sperm. Our study provides structural foundations for understanding sperm evolution, motility, and dysfunction at a molecular level.

Structural specializations of the sperm tail.,Leung MR, Zeng J, Wang X, Roelofs MC, Huang W, Zenezini Chiozzi R, Hevler JF, Heck AJR, Dutcher SK, Brown A, Zhang R, Zeev-Ben-Mordehai T Cell. 2023 Jun 22;186(13):2880-2896.e17. doi: 10.1016/j.cell.2023.05.026. Epub , 2023 Jun 15. PMID:37327785^[4]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Stewart RJ, Farrell KW, Wilson L. Role of GTP hydrolysis in microtubule polymerization: evidence for a coupled hydrolysis mechanism. Biochemistry. 1990 Jul 10;29(27):6489-98. PMID:2207090 doi:10.1021/bi00479a022
↑ Mitchison T, Kirschner M. Dynamic instability of microtubule growth. Nature. 1984 Nov 15-21;312(5991):237-42. PMID:6504138 doi:10.1038/312237a0
↑ Drechsel DN, Kirschner MW. The minimum GTP cap required to stabilize microtubules. Curr Biol. 1994 Dec 1;4(12):1053-61. PMID:7704569 doi:10.1016/s0960-9822(00)00243-8
↑ Leung MR, Zeng J, Wang X, Roelofs MC, Huang W, Zenezini Chiozzi R, Hevler JF, Heck AJR, Dutcher SK, Brown A, Zhang R, Zeev-Ben-Mordehai T. Structural specializations of the sperm tail. Cell. 2023 Jun 22;186(13):2880-2896.e17. PMID:37327785 doi:10.1016/j.cell.2023.05.026