Katanin

Katanin is a microtubule-severing enzyme that plays a crucial role in the regulation of the cytoskeleton in eukaryotic cells. It belongs to the ATP-dependent protease family and specifically targets microtubules, which are key components of the cellular cytoskeleton. Microtubules are involved in various cellular processes, including cell division, intracellular transport, and maintenance of cell shape.

Katanin was first identified in plants, where it was found to regulate microtubule dynamics during cell growth and development. Subsequent research expanded its role across a wide range of organisms, including fungi, animals, and humans. The enzyme exists as a heterodimer, consisting of a large catalytic subunit (Katanin p60) and a smaller regulatory subunit (Katanin p80). The p60 subunit contains the ATPase activity necessary for microtubule severing, while the p80 subunit modulates enzymatic activity and targets katanin to specific cellular locations.

Microtubule severing by katanin involves the hydrolysis of ATP, which induces conformational changes that lead to the cleavage of microtubules at specific sites. This process is essential for several cellular functions, such as the formation of the mitotic spindle during cell division, the remodeling of the cytoskeleton during cell migration, and the generation of short microtubules involved in cellular signaling. Katanin also participates in the regulation of axon branching and dendritic spine formation in neurons, contributing to synaptic plasticity and neural development.

Mutations or dysfunctions in katanin have been linked to various developmental and neurological disorders. For example, defects in katanin activity have been associated with abnormalities in brain structure and function, highlighting its importance in neural development. Additionally, katanin has been implicated in pathological processes such as cancer progression, where altered microtubule dynamics can promote tumor growth and metastasis. Research into katanin continues to uncover its diverse roles in cellular physiology and disease, offering potential targets for therapeutic intervention.