APOBEC

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Enzyme involved in messenger RNA editing

title: "APOBEC" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["ec-3.5.4"] description: "Enzyme involved in messenger RNA editing" topic_path: "general/ec-3-5-4" source: "https://en.wikipedia.org/wiki/APOBEC" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Enzyme involved in messenger RNA editing ::

::data[format=table title="Infobox protein family"]

FieldValue
SymbolAPOBEC_N
NameAPOBEC-like N-terminal domain
PfamPF08210
InterProIPR013158
::

300px|thumb|upright|Example of a member of the APOBEC family, APOBEC-2. A cytidine deaminase from Homo sapiens. | Symbol = APOBEC_N | Name = APOBEC-like N-terminal domain | image = | width = | caption = | Pfam= PF08210 | InterPro= IPR013158 | SMART= | Prosite = | SCOP = | TCDB = | OPM family= | OPM protein= | PDB= | Symbol = APOBEC_C | Name = APOBEC-like C-terminal domain | image = | width = | caption = | Pfam= PF05240 | InterPro= IPR007904 | SMART= | Prosite = | SCOP = | TCDB = | OPM family= | OPM protein= | PDB= APOBEC ("apolipoprotein B mRNA editing enzyme, catalytic polypeptide") is a family of evolutionarily conserved cytidine deaminases.

Function

A mechanism of generating protein diversity is mRNA editing. The APOBEC family of proteins perform mRNA modifications by deaminating cytidine bases to uracil. The N-terminal domain of APOBEC-like proteins is the catalytic domain, while the C-terminal domain is a pseudocatalytic domain. More specifically, the catalytic domain is a zinc dependent cytidine deaminase domain and is essential for cytidine deamination. The positively charged zinc ion in the catalytic domain attracts to the partial-negative charge of RNA.

In the case of APOBEC-1, the mRNA transcript of intestinal apolipoprotein B is altered. RNA editing by APOBEC-1 requires homodimerization and this complex interacts with RNA-binding proteins to form the editosome. The resulting structure interacts with the codon CAA at codon 2153 and deaminates it into UAA, producing a stop codon that results in mRNA that is translated into the intestinal apoB-48 isoform. For other APOBEC-modified transcripts such as in the site-specific deamination of a CGA to a UGA stop codon in neurofibromatosis type 1 (NF1) mRNA, the resulting proteins are predicted to be truncated as well, although these transcripts are possibly degraded.

C-to-U modifications do not always result in the truncation of proteins. For example, in humans/mammals they help protect from viral infections. APOBEC family proteins are widely expressed in cells of the human innate immune system.

Cancer

These enzymes, when misregulated, are a major source of mutation in numerous cancer types. When the expression of APOBEC family proteins is triggered, accidental mutations in somatic cells can lead to the development of oncogenes, cells which have the potential to develop into a tumor. APOBEC proteins are further expressed in attempt to regulate tumor formation. This makes APOBEC proteins a helpful marker for diagnosing malignant tumors.

Structure

A 2013 review discussed the structural and biophysical aspects of APOBEC3 family enzymes. Many of the APOBEC protein features are described in the widely studied APOBEC3G's page.

Family members

Human genes encoding members of the APOBEC protein family include:

References

Bibliography

  • Gupta, A., Gazzo, A., Selenica, P. et al., APOBEC3 mutagenesis drives therapy resistance in breast cancer, Nature Genetics (April 1, 2025)

References

  1. (January 2007). "The APOBEC-2 crystal structure and functional implications for the deaminase AID". Nature.
  2. (April 2003). "Messenger RNA editing in mammals: new members of the APOBEC family seeking roles in the family business". Trends in Genetics.
  3. (19 December 2019). "APOLIPOPROTEIN B mRNA-EDITING ENZYME, CATALYTIC POLYPEPTIDE 1; APOBEC1".
  4. (January 2003). "C-to-U RNA editing: mechanisms leading to genetic diversity". The Journal of Biological Chemistry.
  5. (November 2021). "APOBECs orchestrate genomic and epigenomic editing across health and disease". Trends in Genetics.
  6. (2013). "Intrinsic immunity against retrotransposons by APOBEC cytidine deaminases". Frontiers in Microbiology.
  7. (Dec 2016). "''Unexpected DNA-Binding Mechanism Suggests Ways to Block Enzyme Activity in Cancer''".
  8. (March 2023). "APOBEC3-mediated mutagenesis in cancer: causes, clinical significance and therapeutic potential". Journal of Hematology & Oncology.
  9. (2007-01-01). "AID for Immunoglobulin Diversity". Academic Press.
  10. (November 2013). "Structural features of antiviral DNA cytidine deaminases". Biological Chemistry.

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::

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