TY - JOUR
T1 - Calcium regulation of Myosin-I tension sensing
AU - Lewis, John H.
AU - Greenberg, Michael J.
AU - Laakso, Joseph M.
AU - Shuman, Henry
AU - Ostap, E. Michael
N1 - Funding Information:
This work was supported by the National Institutes of Health (National Institute of General Medical Sciences grant PO1 GM087253 to E.M.O. and H.S., National Institute of Arthritis and Musculoskeletal and Skin Diseases training grant T32 AR053461 to J.H.L. and M.J.G., and grant GM097889 M.J.G.).
PY - 2012/6/20
Y1 - 2012/6/20
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84862696215&partnerID=8YFLogxK
U2 - 10.1016/j.bpj.2012.05.014
DO - 10.1016/j.bpj.2012.05.014
M3 - Article
C2 - 22735530
AN - SCOPUS:84862696215
SN - 0006-3495
VL - 102
SP - 2799
EP - 2807
JO - Biophysical Journal
JF - Biophysical Journal
IS - 12
ER -