The Biology Project
Cell Signaling > Problem
2: Signal Responses I
to help answer the question
Signaling between cells usually results in the activation of protein
Activation of protein
Many classes of receptor bind their ligand and activate protein kinases
inside the cell. Kinases transfer phosphate to specific target proteins
causing a cell response. Activation frequently leads to a protein kinase
cascade, resulting in the rapid amplification of extra-cellular signals.
Some important concepts are:
Problem 2 |
Answer | Problem 3
- Two types of cells may have the same receptor but have different
target proteins for the kinases. This allows the same signal and receptor
to cause different responses.
- The cascade can lead to rapid amplification of the signal, dramatically
speeding up a cell response.
- Responses to signals by phosphate transfers must be reversible.
Phosphatases that remove phosphates are one example of a specific
mechanism to reverse a signal response.
Project > Cell
Biology > Cell
Signaling > Problem
University of Arizona
May 2, 2002
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