8TRN

Actin 1 from T. gondii in filaments bound to MgADP and jasplakinolide

Summary for 8TRN

• Entry DOI: 10.2210/pdb8trn/pdb
• EMDB information: 41584
• Descriptor: Actin, MAGNESIUM ION, ADENOSINE-5'-DIPHOSPHATE, ... (4 entities in total)
• Functional Keywords: actin, cytoskeleton, toxoplasmosis, structural protein
• Biological source: Toxoplasma gondii
• Total number of polymer chains: 3
• Total formula weight: 129353.66

Authors

Hvorecny, K.L.,Sladewski, T.E.,Heaslip, A.T.,Kollman, J.M. (deposition date: 2023-08-09, release date: 2024-03-06)

Primary citation

Hvorecny, K.L.,Sladewski, T.E.,De La Cruz, E.M.,Kollman, J.M.,Heaslip, A.T.
Toxoplasma gondii actin filaments are tuned for rapid disassembly and turnover.
Nat Commun, 15:1840-1840, 2024

PubMed Abstract: The cytoskeletal protein actin plays a critical role in the pathogenicity of the intracellular parasite, Toxoplasma gondii, mediating invasion and egress, cargo transport, and organelle inheritance. Advances in live cell imaging have revealed extensive filamentous actin networks in the Apicomplexan parasite, but there are conflicting data regarding the biochemical and biophysical properties of Toxoplasma actin. Here, we imaged the in vitro assembly of individual Toxoplasma actin filaments in real time, showing that native, unstabilized filaments grow tens of microns in length. Unlike skeletal muscle actin, Toxoplasma filaments intrinsically undergo rapid treadmilling due to a high critical concentration, fast monomer dissociation, and rapid nucleotide exchange. Cryo-EM structures of jasplakinolide-stabilized and native (i.e. unstabilized) filaments show an architecture like skeletal actin, with differences in assembly contacts in the D-loop that explain the dynamic nature of the filament, likely a conserved feature of Apicomplexan actin. This work demonstrates that evolutionary changes at assembly interfaces can tune the dynamic properties of actin filaments without disrupting their conserved structure.

PubMed: 38418447
DOI: 10.1038/s41467-024-46111-3

Experimental method

ELECTRON MICROSCOPY (3 Å)