[Campbell Biology P.168] A mutation causes integrins in a developing animal embryo to lose t... | Practice Question

A mutation causes integrins in a developing animal embryo to lose their ability to bind to intracellular microfilaments, while their extracellular matrix ECM binding remains intact. Which of the following cellular processes would most likely be directly impaired?

  • A: Synthesis of new collagen fibers.
  • B: Transmission of signals from the ECM to the cell's interior, affecting gene expression and cell migration.
  • C: Formation of plasmodesmata between adjacent plant cells.
  • D: Noncovalent attachment of proteoglycan molecules to polysaccharides.

Explanation

The text explicitly states that 'Integrins span the membrane and bind on their cytoplasmic side to associated proteins attached to microfilaments of the cytoskeleton. The name integrin is based on the word integrate: Integrins are in a position to transmit signals between the ECM and the cytoskeleton and thus to integrate changes occurring outside and inside the cell.' It further mentions that this linkage can 'result in changes in cell behavior' and that 'Mechanical signaling involves fibronectin, integrins, and microfilaments of the cytoskeleton' influencing 'cell migration' and 'activity of genes in the nucleus'. Losing the ability to bind to microfilaments would directly disrupt this signal transmission and subsequent cellular responses.