Tail domain

Definition

The tail domain is a structural component of certain molecular motors, like myosin, kinesin, and dynein, which helps in cargo binding and determines the specificity of the motor's function. This region extends from the motor's head, enabling interaction with cellular structures or other proteins. The tail domain plays a crucial role in linking the motor to its cargo and can also influence the motor's stability and activity within cellular environments.

5 Must Know Facts For Your Next Test

1. In myosin, the tail domain varies widely among different types, influencing the type of cargo it can bind to and transport.
2. Kinesins generally have a long coiled-coil tail domain that allows them to dimerize, forming a stable structure for cargo binding.
3. Dynein's tail domain is critical for its function in retrograde transport, enabling it to carry cargo back towards the cell body.
4. The interaction between the tail domain and its cargo is often regulated by post-translational modifications, impacting motor activity.
5. Tail domains can also determine the localization of molecular motors within specific regions of the cell, influencing their overall efficiency.

Review Questions

• How does the tail domain contribute to the functionality of molecular motors like myosin, kinesin, and dynein?
  • The tail domain is essential for the functionality of molecular motors as it directly links the motor to its specific cargo. For instance, in myosin, the variability of the tail domain determines what types of cargo can be bound and transported. In kinesin, the coiled-coil structure helps stabilize the dimeric form necessary for effective transport along microtubules. Similarly, dynein's tail domain plays a critical role in binding to organelles or vesicles for retrograde transport, highlighting how this region influences overall motor function.
• Analyze how variations in the tail domain among different types of myosin affect their role in cellular transport.
  • Variations in the tail domain among different myosins lead to distinct functional roles in cellular transport. For example, myosin II has a tail domain that allows it to form filaments for muscle contraction, while myosin V has a longer tail that enables it to carry larger cargo such as organelles. These differences not only affect binding specificity but also dictate how efficiently each type of myosin can interact with actin filaments and facilitate movement within various cellular contexts.
• Evaluate the impact of post-translational modifications on the activity of molecular motors through their tail domains.
  • Post-translational modifications such as phosphorylation or ubiquitination can significantly impact the activity of molecular motors by altering their tail domains. These modifications can enhance or inhibit cargo binding, change interaction dynamics with other proteins, or affect stability within the cytoskeletal framework. For example, phosphorylation may increase the affinity of a motor for its cargo, leading to enhanced transport efficiency. This regulatory mechanism showcases how cellular signals can modulate motor function through changes in their tail domains, thus influencing overall intracellular transport processes.

Related terms

Cargo: The cellular component or molecule that is transported by molecular motors along cytoskeletal filaments.

Motor domain: The part of a molecular motor responsible for ATP hydrolysis and mechanical movement along filaments.

Cytoskeleton: A network of protein filaments and tubules that provides structural support and facilitates cellular transport.