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Coupling of ATPase activity, microtubule binding, and mechanics in the dynein motor domain
Author(s) -
Niekamp Stefan,
Coudray Nicolas,
Zhang Nan,
Vale Ronald D,
Bhabha Gira
Publication year - 2019
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.15252/embj.2018101414
Subject(s) - dynein , nobel laureate , library science , microtubule , biology , computer science , philosophy , genetics , linguistics , poetry
The movement of a molecular motor protein along a cytoskeletal track requires communication between enzymatic, polymer‐binding, and mechanical elements. Such communication is particularly complex and not well understood in the dynein motor, an ATPase that is comprised of a ring of six AAA domains, a large mechanical element (linker) spanning over the ring, and a microtubule‐binding domain (MTBD) that is separated from the AAA ring by a ~ 135 Å coiled‐coil stalk. We identified mutations in the stalk that disrupt directional motion, have microtubule‐independent hyperactive ATPase activity, and nucleotide‐independent low affinity for microtubules. Cryo‐electron microscopy structures of a mutant that uncouples ATPase activity from directional movement reveal that nucleotide‐dependent conformational changes occur normally in one‐half of the AAA ring, but are disrupted in the other half. The large‐scale linker conformational change observed in the wild‐type protein is also inhibited, revealing that this conformational change is not required for ATP hydrolysis. These results demonstrate an essential role of the stalk in regulating motor activity and coupling conformational changes across the two halves of the AAA ring.