Correct option is A
Correct Answer: (a)
Explanation: β-catenin primarily functions as an intracellular signaling and structural protein involved in the Wnt signaling pathway and cell–cell adhesion. It acts within the responding cell by regulating gene transcription after pathway activation. Unlike secreted ligands or junctional proteins, β-catenin does not itself transmit signals directly to neighbouring cells. Therefore, it does not directly mediate intercellular signal transduction.
Information Booster
· β-catenin acts downstream of Wnt receptors as a transcriptional co-activator.
· It also links cadherins to the actin cytoskeleton in adherens junctions.
· Connexins form gap junctions allowing direct cytoplasmic communication between adjacent cells.
· BMP7 is a secreted growth factor that signals to nearby cells via paracrine signaling.
· Dopamine functions as a neurotransmitter transmitting signals across synapses.
Additional Knowledge
Connexins enable direct transfer of ions and small molecules between neighbouring cells through gap junctions. BMP7 belongs to the TGF-β superfamily and signals to adjacent cells by binding to surface receptors. Dopamine transmits chemical signals between closely apposed neurons. In contrast, β-catenin remains within the cell and functions as an intracellular signaling mediator rather than a molecule that directly conveys signals from one cell to another.
