Subtilisin-cleaved actin: polymerization and interaction with myosin subfragment 1

Biochemistry ◽  
1989 ◽  
Vol 28 (14) ◽  
pp. 5889-5895 ◽  
Author(s):  
Deborah Schwyter ◽  
Martin Phillips ◽  
Emil Reisler
Keyword(s):  
Actin Polymerization ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1

Mechanism of actin polymerization by myosin subfragment-1 probed by dynamic light scattering

2007 ◽  
Vol 70 (1) ◽  
pp. 53-57 ◽  
Author(s):  
A. Galińska-Rakoczy ◽  
Barbara Jachimska ◽  
H. Strzelecka-Gołaszewska
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Actin Polymerization ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1

scholarly journals Elongation of the fertilization tubule in Chlamydomonas: new observations on the core microfilaments and the effect of transient intracellular signals on their structural integrity.

1983 ◽  
Vol 97 (2) ◽  
pp. 522-532 ◽  
Author(s):  
P A Detmers ◽  
U W Goodenough ◽  
J Condeelis
Keyword(s):  
Mating Type ◽  
Actin Filaments ◽  
Actin Polymerization ◽  
Time Course ◽  
Structural Integrity ◽  
Cytochalasin D ◽  
Ultrastructural Observation ◽  
Intracellular Signals ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1

Experimental manipulations of gametes of Chlamydomonas reinhardi and ultrastructural observation were used to examine the composition of the microfilaments in the fertilization tubule, their probable mode of formation, and their interaction with intracellular signals. Decoration with myosin subfragment-1 was used to demonstrate that the microfilaments in the fertilization tubule were actin filaments having uniform polarity: Myosin subfragment-1 arrowheads pointed away from the membrane at the tip of the process. Filaments were attached to the cone-shaped "doublet zone" at the base of the process by their pointed ends. Discrete attachment sites for filaments on the surface of the doublet zone were seen in stereo view. To test whether actin polymerization might accompany elongation of the fertilization tubule, mating gametes were exposed to cytochalasin D in an attempt to block actin polymerization. Treatment of mating type "plus" gametes with cytochalasin D prior to and during mating inhibited the appearance of actin filaments in fertilization tubules, suppressed fertilization tubule outgrowth, and lowered mating efficiency from 90 to 15%. The role of signals generated by flagellar adhesion in maintaining the structural integrity of the microfilament-doublet zone complex was examined by correlating flagellar disadhesion with the kinetics of breakdown of the complex. In zygotes, where flagellar disadhesion occurred after cell fusion, the complex disassembled within 3 h after mating. In gametes that had been agglutinated by isolated mating type "minus" flagella, microfilaments and fertilization tubules progressively disassembled over a 3-h time course following flagellar disadhesion. Disassembly of microfilaments was inhibited by maintaining flagellar agglutination, suggesting that signals generated by flagellar adhesion were necessary to maintain microfilaments intact.

Structure of Myosin Subfragment-1 from Electron Microscopy and Crystallography

1988 ◽  
Vol 46 ◽  
pp. 156-157
Author(s):  
Donald A. Winkelmann
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Actin Filaments ◽  
Light Chains ◽  
Myosin Filament ◽  
Primary Role ◽  
Heavy Chains ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1 ◽  
Globular Head

The primary role of the interaction of actin and myosin is the generation of force and motion as a direct consequence of the cyclic interaction of myosin crossbridges with actin filaments. Myosin is composed of six polypeptides: two heavy chains of molecular weight 220,000 daltons and two pairs of light chains of molecular weight 17,000-23,000. The C-terminal portions of the myosin heavy chains associate to form an α-helical coiled-coil rod which is responsible for myosin filament formation. The N-terminal portion of each heavy chain associates with two different light chains to form a globular head that binds actin and hydrolyses ATP. Myosin can be fragmented by limited proteolysis into several structural and functional domains. It has recently been demonstrated using an in vitro movement assay that the globular head domain, subfragment-1, is sufficient to cause sliding movement of actin filaments.The discovery of conditions for crystallization of the myosin subfragment-1 (S1) has led to a systematic analysis of S1 structure by x-ray crystallography and electron microscopy. Image analysis of electron micrographs of thin sections of small S1 crystals has been used to determine the structure of S1 in the crystal lattice.

scholarly journals Studies of Ligand-induced Conformational Perturbations in Myosin Subfragment 1

1989 ◽  
Vol 264 (18) ◽  
pp. 10810-10819
Author(s):  
K N Rajasekharan ◽  
M Mayadevi ◽  
M Burke
Keyword(s):  
Myosin Subfragment ◽  
Myosin Subfragment 1
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