The nucleosome has an approximate twofold axis of symmetry, called the dyad axis.

TLS Online TPP Program

#Id: 1407

#Unit 4. Cell Communication and Cell Signaling

In the absence of ATP, the myosin head is firmly attached to the actin filament. 

 

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#Id: 1408

#Unit 4. Cell Communication and Cell Signaling

In the presence of ATP,  myosin head releases from the actin filament. 

 

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#Id: 1409

#Unit 4. Cell Communication and Cell Signaling

Thick-filament regulation Myosin-dependent mechanism regulate contraction in smooth muscle and non-muscle cells.

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#Id: 1410

#Unit 4. Cell Communication and Cell Signaling

Smooth muscle cells and nonmuscle cells are regulated by: Norepinephrine, angiotensin, endothelin, histamine

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#Id: 1411

#Unit 4. Cell Communication and Cell Signaling

Smooth muscle contraction is regulated by the cycling of myosin II between on and off states.

     OR

Smooth muscle contraction is regulated by myosin regulatory light chain associated with the myosin II neck domain.

TLS Online TPP Program

#Id: 1412

#Unit 4. Cell Communication and Cell Signaling

In vertebrate smooth muscle, phosphorylation of the myosin regulatory light chain activates contraction in Ca2+ dependent manner.