Katanin

Katanin is a protein that plays a crucial role in the regulation of the cytoskeleton by severing microtubules. It is named after the Japanese sword "katana" due to its ability to cut microtubules into shorter segments. Katanin is composed of two subunits: a 60 kDa catalytic subunit and an 80 kDa regulatory subunit.

Function

Katanin's primary function is to sever microtubules, which are cylindrical structures that are part of the cytoskeleton in eukaryotic cells. This severing activity is essential for various cellular processes, including mitosis, meiosis, and neuronal development. By regulating the length and number of microtubules, katanin influences cell shape, division, and intracellular transport.

Structure

The katanin protein complex consists of two subunits:

• The 60 kDa subunit, known as p60, is responsible for the ATPase activity that provides the energy required for microtubule severing.
• The 80 kDa subunit, known as p80, is involved in targeting the complex to specific cellular locations and regulating the activity of the p60 subunit.

Mechanism

Katanin severs microtubules by hydrolyzing ATP to provide the energy needed for the severing process. The p60 subunit binds to the microtubule and uses the energy from ATP hydrolysis to break the bonds between tubulin subunits, resulting in the severing of the microtubule.

Biological Significance

Katanin is crucial for cell division, as it helps to disassemble the mitotic spindle after chromosome segregation. It also plays a role in neuronal development by regulating the dynamics of microtubules in neurons, which is important for axon growth and dendrite formation.

Clinical Relevance

Mutations or dysregulation of katanin can lead to various neurological disorders and cancer. For example, altered katanin activity has been implicated in Alzheimer's disease and spinal muscular atrophy. Understanding katanin's function and regulation can provide insights into these diseases and potential therapeutic targets.

See Also

• Microtubule-associated proteins
• Cytoskeleton
• Cell division

External Links

• [Katanin at UniProt](https://www.uniprot.org/uniprot/Q12756)
• [Katanin at GeneCards](https://www.genecards.org/cgi-bin/carddisp.pl?gene=KATNA1)

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