BCOR 103 1st Edition Lecture 9 Outline of Last Lecture I The Cytoskeleton II Cytoskeletal Structures III Filament Assembly IV Dynamic Instability Outline of Current Lecture I II III IV Microtubule Associated Proteins MAPs Kinesin and Dynein Structure and Function of Actin Motor Proteins Current Lecture There are seven different MAPs that should be known The first is tubulin ring complex which initiates the formation of a microtubule The second MAP to know is XMAP215 which polymerizes the end of the microtubule Next is Kinesins 8 and 13 which depolymerize the end of the microtubule CLASP and EB1 controls tracking Katanin controls severing the microtubule Tau MAP1 MAP2 and MAP4 work to stabilize the microtubule lengthwise Lastly CLASP is also involved in rescue functions of the microtubules Kinesin is made up of two heavy chains and light chains connected by an alpha helix The heavy chains are two globular proteins that attach to the microtubule The light chains attach to the vesicle or protein being transported within the cell The kinesin works with ATP to move its proteins along the microtubule in the direction toward the positive end of the microtubule Dynein serve a similar function to kinesin except it moves its materials toward the negative end of the microtubule Dynein also has a different structure from kinesin Dynein has two heavy chains that link with the microtubule but the other side is made up of lots of light chains approximately seven The light chains bond with the material being moved and the other heavy chains move along the microtubule G actin is the molecule that actin fibers are made up of Actin monomers G actin come together to form dimers then trimers and eventually a microfilament with a positive and negative end These microfilaments layer together called monomer polymerizing The dimer formin can regulate the end of the microfilament Actin works with the motor proteins These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute that are microfilament based myosin There are many different types of myosin proteins We will focus on the mechanism The myosin head that is connected to a microfilament works in tandem with ATP to attach and release to a parallel actin filament Myosin uses ATP to move up actin This is primarily seen in muscles it is how they contract
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