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Multiple Choice
In cell signaling, which substance directly causes actin filaments to change shape during cytoskeletal rearrangement?
A
DNA polymerase
B
Phospholipase C
C
ATP synthase
D
Rho GTPase
Verified step by step guidance
1
Understand the context: The question is about cell signaling and cytoskeletal rearrangement, specifically focusing on actin filaments. Actin filaments are part of the cytoskeleton, which provides structural support and plays a role in cell movement and shape changes.
Identify the key players: The question lists several molecules (DNA polymerase, Phospholipase C, ATP synthase, and Rho GTPase). Each of these has distinct functions in the cell. For example, DNA polymerase is involved in DNA replication, Phospholipase C is involved in signal transduction, and ATP synthase is responsible for ATP production.
Focus on Rho GTPase: Rho GTPases are a family of small signaling G proteins that regulate the cytoskeleton. They are directly involved in actin filament dynamics, including polymerization, depolymerization, and rearrangement, which are essential for processes like cell migration and shape changes.
Explain the mechanism: Rho GTPases act as molecular switches. When activated (bound to GTP), they interact with downstream effectors such as formins and the Arp2/3 complex, which directly modulate actin filament assembly and organization. This leads to changes in the cytoskeleton's structure and function.
Conclude the reasoning: Based on the roles of the listed molecules, Rho GTPase is the correct answer because it directly causes actin filaments to change shape during cytoskeletal rearrangement. The other molecules listed do not have this specific function.