dyneína

Dynein is a protein complex found in eukaryotic cells that functions as a molecular motor. It is responsible for a variety of cellular movements, including the beating of cilia and flagella, the transport of organelles and vesicles along microtubules, and the separation of chromosomes during cell division. Dyneins are members of the AAA+ ATPase superfamily, meaning they use the energy derived from ATP hydrolysis to generate force and motion.

There are two main families of dynein: cytoplasmic dynein and axonemal dynein. Cytoplasmic dyneins are found in the cytoplasm and are involved in intracellular transport. They move cargo towards the minus end of microtubules, a process known as retrograde transport. Axonemal dyneins are located in the axonemes of cilia and flagella and are responsible for their characteristic beating motion. They generate sliding forces between microtubules that result in bending.

The structure of dynein is complex, consisting of multiple subunits. The core motor function is carried out by a large catalytic domain composed of AAA+ modules. Regulatory subunits associate with the motor domain to control its activity and to bind to specific cargo or structures. The movement of dynein along microtubules involves a power stroke mechanism, where conformational changes in the motor domain driven by ATP hydrolysis result in directed movement. Defects in dynein function are associated with a range of human diseases, including neurodegenerative disorders and primary ciliary dyskinesia, highlighting its critical role in cellular health and function.