Muscle contraction depends on two processes that consume enormous amounts of ATP: 

1. Filament sliding, driven by the ATPase of the myosin

2. Ca2+ pumping, driven by the Ca2+ ATPase

TLS Online TPP Program

#Id: 1537

#Unit 2. Cellular Organization

Class V IF proteins 

Lamins

TLS Online TPP Program

#Id: 1538

#Unit 2. Cellular Organization

Keratins 

make up IF protein classes I and II 

found in epithelia

TLS Online TPP Program

#Id: 1539

#Unit 2. Cellular Organization

Class IV IF proteins compose the neurofilaments found in neurons

TLS Online TPP Program

#Id: 1540

#Unit 2. Cellular Organization

Kinesin-13 (End-Binding Proteins)

• A member of the kinesin motor protein superfamily

• These proteins are ATPases

 

TLS Online TPP Program

#Id: 1541

#Unit 2. Cellular Organization

Kinesin-13 (End-Binding Proteins)

• Bind and curve the end of the tubulin protofilaments into the GDP-β-tubulin conformation

• Facilitate the removal of terminal tubulin dimers 

• Greatly enhancing the frequency of catastrophes

TLS Online TPP Program

#Id: 1542

#Unit 2. Cellular Organization

Op18/stathmin (End-Binding Proteins) binds selectively to curved protofilaments and enhances terminal tubulin heterodimer dissociation from a microtubule end.