Cytoplasmic dynein regulates its attachment to microtubules via nucleotide state-switched mechanosensing at multiple AAA domains.
Cytoplasmic dynein is a homodimeric microtubule (MT) motor protein responsible for most MT minus-end-directed motility. Dynein contains four AAA+ ATPases (AAA: ATPase associated with various cellular activities) per motor domain (AAA1-4). The main site of ATP hydrolysis, AAA1, is the only site considered by most dynein motility models. However, it remains unclear how ATPase activity and MT binding are coordinated within and between dynein's motor domains. Using optical tweezers, we characterize the MT-binding strength of recombinant dynein monomers as a function of mechanical tension and nucleotide state. Dynein responds anisotropically to tension, binding tighter to MTs when pulled toward the MT plus end. We provide evidence that this behavior results from an asymmetrical bond that acts as a slip bond under forward tension and a slip-ideal bond under backward tension. ATP weakens MT binding and reduces bond strength anisotropy, and unexpectedly, so does ADP. Using nucleotide binding and hydrolysis mutants, we show that, although ATP exerts its effects via binding AAA1, ADP effects are mediated by AAA3. Finally, we demonstrate "gating" of AAA1 function by AAA3. When tension is absent or applied via dynein's C terminus, ATP binding to AAA1 induces MT release only if AAA3 is in the posthydrolysis state. However, when tension is applied to the linker, ATP binding to AAA3 is sufficient to "open" the gate. These results elucidate the mechanisms of dynein-MT interactions, identify regulatory roles for AAA3, and help define the interplay between mechanical tension and nucleotide state in regulating dynein motility.
Department of Anatomy and Structural Biology, Gruss Lipper Biophotonics Center, and Medical Scientist Training Program, Albert Einstein College of Medicine, Bronx, NY 10461;
Matthew P
MP
Nicholas
Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany; Laboratory of Sensory Neuroscience, and Howard Hughes Medical Institute, Rockefeller University, New York, NY 10065; and.
Florian
F
Berger
Department of Anatomy and Structural Biology, Gruss Lipper Biophotonics Center, and.
Lu
L
Rao
Department of Anatomy and Structural Biology, Gruss Lipper Biophotonics Center, and.
Sibylle
S
Brenner
Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305.
Carol
C
Cho
Department of Anatomy and Structural Biology, Gruss Lipper Biophotonics Center, and arne.gennerich@einstein.yu.edu.
Arne
A
Gennerich
D000123:Acetyltransferases / Q000378:metabolism*; D016880:Anisotropy; D001696:Biomechanical Phenomena; D003593:Cytoplasm / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D004398:Dyneins / Q000302:isolation & purification / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000276:immunology; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D008870:Microtubules / Q000378:metabolism*; D016296:Mutagenesis; D052898:Optical Tweezers; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000378:metabolism / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
D017931:DNA Primers; C540859:NAT1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins; D000123:Acetyltransferases; D004398:Dyneins
AAA+ ATPases; cytoplasmic dynein; mechanosensing; microtubules; optical tweezers