Summary

Name TOP1
Full Name DNA topoisomerase 1
Synonyms DNA topoisomerase I
Primary ID P11387
Links - -
Type protein
Relations 12
Inhibitors topotecan; irinotecan
Function Releases the supercoiling and torsional tension of DNA introduced during the DNA replication and transcription by transiently cleaving and rejoining one strand of the DNA duplex. Introduces a single-strand break via transesterification at a target site in duplex DNA. The scissile phosphodiester is attacked by the catalytic tyrosine of the enzyme, resulting in the formation of a DNA-(3'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 5'-OH DNA strand. The free DNA strand then rotates around the intact phosphodiester bond on the opposing strand, thus removing DNA supercoils. Finally, in the religation step, the DNA 5'-OH attacks the covalent intermediate to expel the active-site tyrosine and restore the DNA phosphodiester backbone (By similarity). Regulates the alternative splicing of tissue factor (F3) pre-mRNA in endothelial cells. Involved in the circadian transcription of the core circadian clock component ARNTL/BMAL1 by altering the chromatin structure around the ROR response elements (ROREs) on the ARNTL/BMAL1 promoter.

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Modifications Tables

Relations

Regulator Mechanism target score
+ up-regulates activity img/direct-activation.png phosphorylation TOP1 0.391
Publications: 1 Organism: In Vitro
+ down-regulates quantity by destabilization img/direct_inhibition.png phosphorylation TOP1 0.46
Publications: 1 Organism: Homo Sapiens
+ up-regulates activity img/direct-activation.png phosphorylation TOP1 0.358
Publications: 2 Organism: In Vitro
+ up-regulates activity img/direct-activation.png phosphorylation TOP1 0.2
Publications: 1 Organism: In Vitro
+ up-regulates activity img/direct-activation.png phosphorylation TOP1 0.408
Publications: 1 Organism: Homo Sapiens
+ up-regulates img/direct-activation.png binding TOP1 0.379
Publications: 1 Organism: Homo Sapiens
+ down-regulates quantity by repression img/direct_inhibition.png transcriptional regulation ARNTL 0.349
Publications: 1 Organism: Mus Musculus
+ down-regulates activity img/direct_inhibition.png chemical inhibition TOP1 0.8
Publications: 1 Organism: Homo Sapiens
+ down-regulates quantity by destabilization img/direct_inhibition.png ubiquitination TOP1 0.476
Publications: 1 Organism: Homo Sapiens
+ down-regulates activity img/direct_inhibition.png chemical inhibition TOP1 0.8
Publications: 1 Organism: Homo Sapiens
+ up-regulates img/direct-activation.png binding TOP1 0.382
Publications: 1 Organism: Homo Sapiens