Regulation of sister chromatid separation at the metaphase-anaphase transition (Homo sapiens)

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1Chromosomes alignUbiquitin-mediateddegradationSpindle checkpoint ONChromosomes attach to spindleESPL1SMC1AMAD1L1CDC20MAD2L1PBUB1BUB1BBUB3CENPEANAPC2ANAPC11PTTG1ESPL1PTTG1UbPrometaphaseMetaphaseAnaphaseSeparation of sister chromatidsSMC3RAD21STAG1ESPL1PChromosomes separateSpindle checkpoint OFF


In prometaphase, highly condensed chromosomes establish bipolar attachments to the mitotic spindle. Unattached or mal-orientated chromosomes generate a signal to delay the onset of anaphase until all pairs of sister chromatids are properly aligned on the metaphase plate. This signal is transduced by a relay of spindle-checkpoint proteins, including MAD1, MAD2, BUB1, BUBR1, BUB3 and centrosome protein E (CENPE), which inhibits cell division cycle 20 (CDC20)-mediated activation of an E3 ubiquitin ligase, the anaphase promoting complex/cyclosome (APC/C). Following attachment and alignment of all the chromosomes at metaphase, the checkpoint signal is silenced and APC/C initiates the ubiquitin-dependent degradation of securin and activation of separase. Separase in turn cleaves a multiprotein complex termed cohesin, which creates physical links between sister chromatids to initiate anaphase.

This process may be of interest in colorectal cancer, specifically in terms of the chromosome instability phenotype, which could result from defects in pathways that ensure accurate chromosome segregation.

Adapted from Pino et al.

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Ontology Terms



  1. Pino MS, Chung DC; ''The chromosomal instability pathway in colon cancer.''; Gastroenterology, 2010 PubMed


96623view17:27, 23 March 2018KhanspersModified description
96621view17:23, 23 March 2018KhanspersOntology Term : 'cell cycle pathway, mitotic' added !
96620view17:20, 23 March 2018KhanspersModified description
96619view17:19, 23 March 2018KhanspersNew pathway

External references


View all...
NameTypeDatabase referenceComment
ANAPC11GeneProductENSG00000141552 (Ensembl)
ANAPC2GeneProductENSG00000176248 (Ensembl)
BUB1BGeneProductENSG00000156970 (Ensembl)
BUB1GeneProductENSG00000169679 (Ensembl)
BUB3GeneProductENSG00000154473 (Ensembl)
CDC20GeneProductENSG00000117399 (Ensembl)
CENPEGeneProductENSG00000138778 (Ensembl)
ESPL1GeneProductENSG00000135476 (Ensembl)
MAD1L1GeneProductENSG00000002822 (Ensembl)
MAD2L1GeneProductENSG00000164109 (Ensembl)
PTTG1GeneProductENSG00000164611 (Ensembl)
RAD21GeneProductENSG00000164754 (Ensembl)
SMC1AGeneProductENSG00000072501 (Ensembl)
SMC3GeneProductENSG00000108055 (Ensembl)
STAG1GeneProductENSG00000118007 (Ensembl)

Annotated Interactions

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