9KBW

CryoEM structure of microtubule bound with GAS2-GAR domain.

Summary for 9KBW

• Entry DOI: 10.2210/pdb9kbw/pdb
• EMDB information: 62232
• Descriptor: Growth arrest-specific protein 2, Tubulin beta chain, Detyrosinated tubulin alpha-1B chain, ... (6 entities in total)
• Functional Keywords: cytoskeleton, structural protein
• Biological source: Mus musculus (house mouse); More
• Total number of polymer chains: 3
• Total formula weight: 106229.41

Authors

An, J.,Imasaki, T.,Narita, A.,Niwa, S.,Sasaki, R.,Makino, T.,Nitta, R.,Kikkawa, M. (deposition date: 2024-10-31, release date: 2025-09-10)

Primary citation

An, J.,Imasaki, T.,Narita, A.,Niwa, S.,Sasaki, R.,Makino, T.,Nitta, R.,Kikkawa, M.
Dimerization of GAS2 mediates crosslinking of microtubules and F-actin.
Embo J., 44:2997-3024, 2025

PubMed Abstract: The spectraplakin family protein GAS2 was originally identified as a growth arrest-specific protein, and recent studies have revealed its involvement in multiple cellular processes. Its dual interaction with actin filaments and microtubules highlights its essential role in cytoskeletal organization, such as cell division, apoptosis, and possibly tumorigenesis. However, the structural basis of cytoskeletal dynamics regulation by GAS2 remains unclear. In this study, we present cryo-electron microscopy structures of the GAS2 type 3 calponin homology domain (CH3) in complex with F-actin at 2.8 Å resolution, thus solving the first type CH3 domain structure bound to F-actin and confirming its actin-binding activity. We also provide the first near-atomic resolution cryo-EM structure of the GAS2-GAR domain bound to microtubules and identify conserved microtubule-binding residues. Our biochemical experiments show that GAS2 promotes microtubule nucleation and polymerization, and that its C-terminal region is essential for dimerization, bundling of both F-actin and microtubules, and microtubule nucleation. As mutations leading to expression of C-terminally truncated GAS2 have been linked to hearing loss, these findings suggest that the disruption of GAS2-dependent cytoskeletal organisation could underlie auditory dysfunction.

PubMed: 40169809
DOI: 10.1038/s44318-025-00415-2

Experimental method

ELECTRON MICROSCOPY (3.2 Å)