The localization and translational control of actin mRNA is important for the migration of fibroblasts and is regulated by the activity of the kinase Src (see Figure 18.10). Src is activated by phosphorylation when cell surface receptors bind to signaling molecules. How might this system lead to a cell migrating in a specific direction? How might the cell migrate away from repulsive signals?

Verified step by step guidance

1. Understand that Src kinase is activated by phosphorylation when cell surface receptors bind to signaling molecules, which is a key step in the signaling pathway.
2. Recognize that the localization and translational control of actin mRNA is crucial for the formation of actin filaments, which are essential for cell movement.
3. Consider how the activation of Src kinase can lead to the localized translation of actin mRNA at the leading edge of the cell, promoting actin polymerization and cell movement in that direction.
4. Think about how repulsive signals might lead to the deactivation of Src kinase or the activation of other pathways that inhibit actin polymerization at certain parts of the cell, causing the cell to move away from these signals.
5. Integrate these concepts to understand how the spatial regulation of Src activity and actin mRNA localization can direct cell migration towards attractive signals and away from repulsive ones.

Key Concepts

Actin mRNA Localization

Actin mRNA localization refers to the spatial distribution of actin messenger RNA within the cell, which is crucial for directing the synthesis of actin proteins at specific sites. This process allows fibroblasts to polarize and form structures necessary for movement, enabling them to migrate toward growth factors or wound sites.

Src Kinase Activation

Src is a non-receptor tyrosine kinase that plays a pivotal role in cell signaling pathways. It is activated through phosphorylation when cell surface receptors interact with ligands, leading to downstream effects that promote cytoskeletal rearrangements and cell motility, essential for directional migration.

Directional Migration and Repulsive Signals

Directional migration involves the ability of cells to move toward attractive signals (chemotaxis) or away from repulsive signals (chemorepulsion). Cells can migrate away from repulsive signals by altering their cytoskeletal dynamics and signaling pathways, allowing them to navigate complex environments and avoid unfavorable conditions.