scholarly journals Localization of a myosin subfragment-1 interaction site on the C-terminal part of actin

1992 ◽  
Vol 284 (1) ◽  
pp. 75-79 ◽  
Author(s):  
J P Labbé ◽  
M Boyer ◽  
C Roustan ◽  
Y Benyamin
Keyword(s):  
Conformational Changes ◽  
Light Chain ◽  
Myosin Head ◽  
Terminal Region ◽  
Terminal Part ◽  
Rigor State ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1 ◽  
Chain Interaction ◽  
Rule Out

The actin-myosin head complex in the rigor state reveals several high-affinity sites on the actin molecule in sequences 18-28 and 40-113. In the presence of Mg(2+)-ATP, participation of the actin N-terminal 1-7 sequence is known to occur. The proximity of the C-terminal region of actin to the A1 light chain of the myosin head [S-1(A1)] (where S-1 is myosin subfragment-1) was described previously. We observed that C-terminal antigenic structures located near Met-305, Met-325 and Met-355 and the C-terminal end (Cys-374) of actin are markedly modified in the presence of S-1(A1), S-1(A2) and scallop S-1 and in the absence of Mg(2+)-ATP. This seems to rule out any important specific involvement of the A1 light chain in the described conformational changes. An S-1-binding site was located in this actin C-terminal region by testing the tryptic CB9 peptide (360-372 sequence) previously implicated in the A1 light chain interaction. This peptide was able to bind well to S-1(A1), S-1(A2) and scallop S-1, but not in the presence of Mg(2+)-pyrophosphate. These results strengthen the hypothesis of a multisite interface between S-1 and actin located in the actin subdomain I.

Antigenic probes locate the myosin subfragment 1 interaction site on the N-terminal part of actin

1986 ◽  
Vol 6 (5) ◽  
pp. 493-499 ◽  
Author(s):  
C. Méjean ◽  
M. Boyer ◽  
J. P. Labbé ◽  
J. Derancourt ◽  
Y. Benyamin ◽  
...  
Keyword(s):  
Contact Area ◽  
Polypeptide Chain ◽  
Myosin Head ◽  
Terminal Part ◽  
Interaction Site ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1

The interaction of two different anti-actin antibody populations with the myosin subfragment 1-F-actin rigor complex has been studied. In contrast with the 1–7 sequence, the 18–28 sequence appears to be strongly implicated in the contact area of the myosin head on the actin polypeptide chain.

scholarly journals Binding of myosin subfragment 1 to glycerinated insect flight muscle in the rigor state

1985 ◽  
Vol 47 (2) ◽  
pp. 151-169 ◽  
Author(s):  
R.S. Goody ◽  
M.C. Reedy ◽  
W. Hofmann ◽  
K.C. Holmes ◽  
M.K. Reedy
Keyword(s):  
Flight Muscle ◽  
Insect Flight ◽  
Insect Flight Muscle ◽  
Rigor State ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1

scholarly journals Molecular Mechanisms of Muscle Weakness Associated with E173A Mutation in Tpm3.12. Troponin Ca2+ Sensitivity Inhibitor W7 Can Reduce the Damaging Effect of This Mutation

2020 ◽  
Vol 21 (12) ◽  
pp. 4421
Author(s):  
Yurii S. Borovikov ◽  
Armen O. Simonyan ◽  
Stanislava V. Avrova ◽  
Vladimir V. Sirenko ◽  
Charles S. Redwood ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Muscle Weakness ◽  
Conformational Changes ◽  
Molecular Mechanisms ◽  
Spatial Arrangement ◽  
Muscle Fibres ◽  
Thin Filaments ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1

Substitution of Ala for Glu residue in position 173 of γ-tropomyosin (Tpm3.12) is associated with muscle weakness. Here we observe that this mutation increases myofilament Ca2+-sensitivity and inhibits in vitro actin-activated ATPase activity of myosin subfragment-1 at high Ca2+. In order to determine the critical conformational changes in myosin, actin and tropomyosin caused by the mutation, we used the technique of polarized fluorimetry. It was found that this mutation changes the spatial arrangement of actin monomers and myosin heads, and the position of the mutant tropomyosin on the thin filaments in muscle fibres at various mimicked stages of the ATPase cycle. At low Ca2+ the E173A mutant tropomyosin shifts towards the inner domains of actin at all stages of the cycle, and this is accompanied by an increase in the number of switched-on actin monomers and myosin heads strongly bound to F-actin even at relaxation. Contrarily, at high Ca2+ the amount of the strongly bound myosin heads slightly decreases. These changes in the balance of the strongly bound myosin heads in the ATPase cycle may underlie the occurrence of muscle weakness. W7, an inhibitor of troponin Ca2+-sensitivity, restores the increase in the number of myosin heads strongly bound to F-actin at high Ca2+ and stops their strong binding at relaxation, suggesting the possibility of using Ca2+-desensitizers to reduce the damaging effect of the E173A mutation on muscle fibre contractility.

scholarly journals The molecular organization of myosin in stress fibers of cultured cells.

1986 ◽  
Vol 102 (1) ◽  
pp. 200-209 ◽  
Author(s):  
G Langanger ◽  
M Moeremans ◽  
G Daneels ◽  
A Sobieszek ◽  
M De Brabander ◽  
...  
Keyword(s):  
Light Chain ◽  
Cultured Cells ◽  
Staining Pattern ◽  
Central Zone ◽  
Molecular Organization ◽  
Stress Fibers ◽  
General Distribution ◽  
Immunogold Staining ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1

Antibodies to chicken gizzard myosin, subfragment 1, light chain 20, and light meromyosin were used to visualize myosin in stress fibers of cultured chicken cells. The antibody specificity was tested on purified gizzard proteins and total cell lysates using immunogold silver staining on protein blots. Immunofluorescence on cultured chicken fibroblasts and epithelial cells exhibited a similar staining pattern of antibodies to total myosin, subfragment 1, and light chain 20, whereas the antibodies to light meromyosin showed a substantially different reaction. The electron microscopic distribution of these antibodies was investigated using the indirect and direct immunogold staining method on permeabilized and fixed cells. The indirect approach enabled us to describe the general distribution of myosin in stress fibers. Direct double immunogold labeling, however, provided more detailed information on the orientation of myosin molecules and their localization relative to alpha-actinin: alpha-actinin, identified with antibodies coupled to 10-nm gold, was concentrated in the dense bodies or electron-dense bands of stress fibers, whereas myosin was confined to the intervening electron-lucid regions. Depending on the antibodies used in combination with alpha-actinin, the intervening regions revealed a different staining pattern: antibodies to myosin (reactive with the head portion of nonmuscle myosin) and to light chain 20 (both coupled to 5-nm gold) labeled two opposite bands adjacent to alpha-actinin, and antibodies to light meromyosin (coupled to 5-nm gold) labeled a single central zone. Based on these results, we conclude that myosin in stress fibers is organized into bipolar filaments.

Sign in / Sign up

Export Citation Format

Share Document