View source for Dyneins

There are two types of [[Microtubules|microtubule]] motor proteins these are [[Kinesins|kinesins]] and dyneins. They have globular heads which bind to the microtubule and also bind [[ATP|ATP]]. The [[Hydrolysis|hydrolysis]] of ATP is what drives movement. The tail regions of the motor proteins bind the cargo e.g. [[Endoplasmic reticulum|endoplasmic reticulum]], [[Golgi apparatus|Golgi apparatus]]. The dyneins are a family of minus-end-directed microtubule motors, whereas kinesins are plus-end-directed motors <ref>Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008) Molecular Biology of the cell, fifth edition, New York: Garland Science.</ref>. Dyneins are composed of two or three heavy chains and a large variable number of associated intermediate and light chains <ref>Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008) Molecular Biology of the cell, fifth edition, New York: Garland Science.</ref>. The dyneins family consists of two major branches, cytoplasmic dynein and axonemal dynein <ref>Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008) Molecular Biology of the cell, fifth edition, New York: Garland Science.</ref>. 

=== Cytoplasmic Dynein  ===

Cytoplasmic dynein is typically composed of heavy chain homodimers, with two large motor domains as heads <ref>Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008) Molecular Biology of the cell, fifth edition, New York: Garland Science.</ref>. These are found in probably all [[Eukaryotic cells|eukaryotic cells]] as they are important for vesicle trafficking and for the localization of the Golgi apparatus near to the centre of the cell <ref>Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008) Molecular Biology of the cell, fifth edition, New York: Garland Science.</ref>. Cytoplasmic dynein has molecular mass of about 1.5 Megadaltons <ref>Wikipedia (2011) Dynein [Online] Available at: http://en.wikipedia.org/wiki/Dynein ( last accessed 28.11.2011).</ref>. Cytoplasmic dynein transports its cargo by “walking” along the microtubule without becoming detached <ref>Wikipedia (2011) Dynein [Online] Available at: http://en.wikipedia.org/wiki/Dynein ( last accessed 28.11.2011).</ref>. 

=== Axonemal dyneins  ===

Axonemal dynein includes heterodimers, two motor-domain heads, and heterotrimers, three motor-domain heads <ref>Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008) Molecular Biology of the cell, fifth edition, New York: Garland Science.</ref>. These are highly specialised for sliding movements of microtubules that drive the beating of [[Cilia|cilia]] and [[Flagella|flagella]] <ref>Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008) Molecular Biology of the cell, fifth edition, New York: Garland Science.</ref>. In a test tube axonemal dyneins can move microtubules at a rate of 14µm/sec <ref>Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008) Molecular Biology of the cell, fifth edition, New York: Garland Science.</ref>. This is far faster than kinesins which are only able to move at speeds of around 2-3µm/sec <ref>Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008) Molecular Biology of the cell, fifth edition, New York: Garland Science.</ref>.&nbsp; 

=== References  ===

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