# Phosphorylation

Source: https://onco.cc/terms/phosphorylation/  
OnCo record `phosphorylation` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Attaching a small phosphate tag to a protein, which changes its shape and switches it on or off. It is the cell's main way of passing signals from one protein to the next.

## Summary

Kinases add phosphates and phosphatases remove them, so the balance of the two determines whether a signal is flowing. In a growth pathway, each protein is phosphorylated by the one above it and then phosphorylates the one below, which is why a single stuck kinase can light up the entire chain. Detecting phosphorylated proteins (phospho-ERK, phospho-AKT) in tumour tissue is a direct readout of whether a pathway is active and whether a drug has actually switched it off.

## Fields

- Kind: Term
- Last checked: 2026-09-09
- Also known as: phosphorylated; phosphorylates; phosphate group; phosphate groups; dephosphorylation; phospho-; phosphorylate

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Protein_phosphorylation
- Wikipedia: https://en.wikipedia.org/wiki/Protein_phosphorylation

## Connected records

- terms: [Enzyme](https://onco.cc/terms/enzyme/), [Growth signal](https://onco.cc/terms/growth-signal/), [Kinase](https://onco.cc/terms/kinase/), [Signalling pathway](https://onco.cc/terms/signalling-pathway/)
- pathways: [PI3K / AKT / mTOR](https://onco.cc/pathways/pi3k-akt-mtor/), [RAS / RAF / MEK / ERK (MAPK)](https://onco.cc/pathways/ras-mapk/)

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JSON: https://onco.cc/api/v1/entities/phosphorylation.json