# BUB1

Source: https://onco.cc/targets/bub1/  
OnCo record `bub1` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

BUB1 is one of the kinases that stops a dividing cell pulling its chromosomes apart before every one is attached. Inhibitors exist in the laboratory; none has reached patients.

## Summary

BUB1 (chromosome 2q13) is a serine/threonine kinase essential for spindle-assembly-checkpoint signalling and correct chromosome alignment: it assembles checkpoint proteins at the kinetochore, being required for the localisation of CENPF, BUB1B, CENPE and MAD2L1 and of PLK1, and for centromeric enrichment of cohesion factors. Expression is high in testis and thymus, lower in colon, spleen, lung and small intestine, and associated with tissues of high mitotic index (UniProt O43683). A ClinicalTrials.gov search for the tool inhibitor BAY 1816032 returned no studies.

## Fields

- Kind: Target
- Last checked: 2026-09-24
- Also known as: BUB1 mitotic checkpoint serine/threonine kinase; hBUB1; BUB1L
- Tags: checkpoint-map
- Symbol: BUB1
- Class: kinase
- Biology: A kinetochore kinase of the spindle assembly checkpoint, alongside MPS1 (TTK) and BUB1B.
- Where found: Tissues with a high mitotic index (UniProt O43683)

## Notes

- Prevalence not recorded: HGNC and UniProt carry no positivity rates.

## Sources

- HGNC HGNC:1148: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:1148
- UniProt O43683: https://www.uniprot.org/uniprotkb/O43683/entry
- NCBI Gene 699: https://www.ncbi.nlm.nih.gov/gene/699

## Connected records

- targets: [AURKB](https://onco.cc/targets/aurkb/), [MPS1 (TTK)](https://onco.cc/targets/ttk/), [PLK1](https://onco.cc/targets/plk1/)
- pathways: [Mitosis & the spindle assembly checkpoint](https://onco.cc/pathways/mitotic-spindle-checkpoint/)
- terms: [Checkpoint (two meanings)](https://onco.cc/terms/checkpoint/)

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JSON: https://onco.cc/api/v1/entities/bub1.json