Dynein

Definition

Dynein is a type of molecular motor protein that moves along microtubules in cells, primarily transporting cellular cargo towards the minus end of the microtubule. This movement is essential for various cellular functions, including organelle transport, mitosis, and flagellar motion, highlighting its importance in both muscle contraction and cell motility.

5 Must Know Facts For Your Next Test

1. Dynein is unique among molecular motors because it is responsible for retrograde transport, moving cargo toward the cell body in neurons.
2. This motor protein is powered by ATP hydrolysis, converting chemical energy into mechanical work to facilitate movement along microtubules.
3. In muscle cells, dynein interacts with other proteins to coordinate contraction by helping transport signaling molecules and organelles.
4. Ciliary and flagellar beating relies heavily on dynein activity to generate the sliding motion between microtubule doublets, enabling cell motility.
5. Mutations or dysfunctions in dynein can lead to serious diseases, including neurodegenerative disorders and ciliopathies, which affect organ function.

Review Questions

• How does dynein contribute to intracellular transport compared to kinesin?
  • Dynein and kinesin are both essential motor proteins that move along microtubules but in opposite directions. While dynein transports cellular cargo toward the minus end of the microtubule, typically towards the cell body, kinesin moves cargo toward the plus end, away from the center of the cell. This complementary action is crucial for maintaining cellular organization and transporting various materials necessary for cell function.
• Discuss the role of dynein in ciliary movement and its significance for cellular motility.
  • Dynein plays a vital role in the movement of cilia and flagella by enabling the sliding of microtubule doublets. When dynein attaches to one doublet and pulls it relative to another, this creates bending motion that propels the cilia or flagella. This mechanism is essential for many single-celled organisms to swim and for multicellular organisms to move fluids across their epithelial surfaces, highlighting dynein's importance in overall cellular motility.
• Evaluate how dysfunction in dynein can impact human health and contribute to specific diseases.
  • Dysfunction in dynein can lead to several health issues due to its critical roles in intracellular transport and ciliary function. For example, mutations in dynein genes can result in neurodegenerative diseases where proper transport of organelles is disrupted, leading to neuronal damage. Additionally, conditions like primary ciliary dyskinesia arise from defective dynein, which impairs ciliary function, resulting in respiratory issues and other systemic effects. Understanding these impacts underscores the importance of dynein in maintaining cellular health.

Related terms

Microtubules: Cylindrical structures made of tubulin protein that provide structural support and facilitate intracellular transport.

Kinesin: Another type of motor protein that typically moves along microtubules towards the plus end, playing a key role in anterograde transport within cells.

Cilia: Short, hair-like structures on the surface of some cells that enable movement and play a role in fluid movement across cell surfaces, often powered by dynein.