Abstract:
:Myo1b is a myosin that is exquisitely sensitive to tension. Its actin-attachment lifetime increases > 50-fold when its working stroke is opposed by 1 pN of force. The long attachment lifetime of myo1b under load raises the question: how are actin attachments that last >50 s in the presence of force regulated? Like most myosins, forces are transmitted to the myo1b motor through a light-chain binding domain that is structurally stabilized by calmodulin, a calcium-binding protein. Thus, we examined the effect of calcium on myo1b motility using ensemble and single-molecule techniques. Calcium accelerates key biochemical transitions on the ATPase pathway, decreases the working-stroke displacement, and greatly reduces the ability of myo1b to sense tension. Thus, calcium provides an effective mechanism for inhibiting motility and terminating long-duration attachments.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Lewis JH,Greenberg MJ,Laakso JM,Shuman H,Ostap EMdoi
10.1016/j.bpj.2012.05.014subject
Has Abstractpub_date
2012-06-20 00:00:00pages
2799-807issue
12eissn
0006-3495issn
1542-0086pii
S0006-3495(12)00567-Xjournal_volume
102pub_type
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