TY - JOUR
T1 - Dynein as a microtubule translocator in ciliary motility
T2 - current studies of arm structure and activity pattern.
AU - Satir, P.
PY - 1988
Y1 - 1988
N2 - The dynein arms of ciliary doublet microtubules cause adjacent axonemal doublets to slide apart with fixed polarity. This suggests that there is a unique mechanochemistry to the dynein arm with unidirectional force generation in all active arms and also that not all arms are active at once during a ciliary beat. Negative stain and thin-section images of arms in axonemes treated with beta, gamma methylene adenosine triphosphate (AMP-PCP) show a consistent subunit construction where the globular head of the arm interacts with subfiber B of doublet N+1. This interpretation differs from that provided by freeze etch and STEM interpretations of in situ arm construction and has implications for the mechanochemical cycle of the arm. A computer model of the arms in relation to other axonemal structures has been constructed to test these interpretations. Attachment of the head of the arm subfiber B is directly demonstrable in splayed axonemes in AMP-PCP. About half of the doublets in an axoneme show such attachments, while half do not. This might imply that about half the doublets in an axoneme are active at any given instant and can be identified as such. This information may be useful in probing questions of how active arms differ biochemically from inactive arms and of how microtubule translocators in general become active.
AB - The dynein arms of ciliary doublet microtubules cause adjacent axonemal doublets to slide apart with fixed polarity. This suggests that there is a unique mechanochemistry to the dynein arm with unidirectional force generation in all active arms and also that not all arms are active at once during a ciliary beat. Negative stain and thin-section images of arms in axonemes treated with beta, gamma methylene adenosine triphosphate (AMP-PCP) show a consistent subunit construction where the globular head of the arm interacts with subfiber B of doublet N+1. This interpretation differs from that provided by freeze etch and STEM interpretations of in situ arm construction and has implications for the mechanochemical cycle of the arm. A computer model of the arms in relation to other axonemal structures has been constructed to test these interpretations. Attachment of the head of the arm subfiber B is directly demonstrable in splayed axonemes in AMP-PCP. About half of the doublets in an axoneme show such attachments, while half do not. This might imply that about half the doublets in an axoneme are active at any given instant and can be identified as such. This information may be useful in probing questions of how active arms differ biochemically from inactive arms and of how microtubule translocators in general become active.
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U2 - 10.1002/cm.970100131
DO - 10.1002/cm.970100131
M3 - Article
C2 - 2972400
AN - SCOPUS:0023782751
SN - 0886-1544
VL - 10
SP - 263
EP - 270
JO - Cell Motility and the Cytoskeleton
JF - Cell Motility and the Cytoskeleton
IS - 1-2
ER -