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. 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 in response to external signals binding to cell surface receptors, which initiates intracellular signaling pathways.
2. Recognize that activated Src can regulate the localization and translation of actin mRNA, leading to localized actin protein synthesis at specific regions of the cell.
3. Consider that localized actin polymerization at the leading edge of the cell promotes protrusion and movement toward attractive signals, effectively guiding directional migration.
4. For migration away from repulsive signals, understand that Src activity might be inhibited or differently regulated in regions of the cell exposed to these signals, reducing actin polymerization there and causing the cell to move in the opposite direction.
5. Integrate these concepts to see how spatial regulation of Src activity and actin mRNA translation creates asymmetry in the cytoskeleton, enabling the cell to migrate directionally in response to both attractive and repulsive cues.

Key Concepts

mRNA Localization and Translational Control

mRNA localization refers to the spatial distribution of mRNA molecules within a cell, allowing proteins to be synthesized at specific sites. Translational control regulates when and where these mRNAs are translated into proteins, enabling localized responses such as actin polymerization at the leading edge during cell migration.

Src Kinase Activation and Signal Transduction

Src is a tyrosine kinase activated by phosphorylation upon receptor binding to extracellular signals. Activated Src transmits signals inside the cell, modulating downstream pathways that influence cytoskeletal dynamics and mRNA translation, thereby directing cellular behaviors like migration.

Directional Cell Migration and Response to Guidance Cues

Cells migrate directionally by interpreting attractive and repulsive signals through surface receptors. Attractive signals activate pathways promoting actin assembly at the front, while repulsive signals inhibit these processes or promote disassembly, enabling the cell to move toward favorable environments and away from harmful stimuli.