Family with sequence similarity 222 member A or Aggregatin is a protein of unknown function. In humans it is encoded by the gene FAM222A. Aggregatin's cellular function is not well understood, however it has been implicated in Alzheimer's disease.[5]

FAM222A
Identifiers
AliasesFAM222A, C12orf34, family with sequence similarity 222 member A
External IDsMGI: 3605543; HomoloGene: 41895; GeneCards: FAM222A; OMA:FAM222A - orthologs
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_032829

NM_001004180

RefSeq (protein)

NP_116218

NP_001004180

Location (UCSC)Chr 12: 109.71 – 109.77 MbChr 5: 114.71 – 114.75 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

Gene

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FAM222A is also called C12orf34.[6] It is located on chromosome 12 at q24.11.[7] It encompasses 56,672 bp.[7] The mRNA is 3,685 bp while the coding region is 1,359 bp.[7]

FAM222A is highly expressed in the brain and spinal cord.[8] It is expressed to a lesser extent in the cerebellum, pituitary gland, adrenal gland and testis.[8]

mRNA

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It has 3 different splice variants of mRNA.[6] The most common mRNA is 3,685 bp while the coding region is 1,359 bp.[6] The mRNA consists of three exons and has two different isoforms in humans. The Kozak Sequence is not very well conserved in FAM222A and it has a non-canonical polyadenylation site.

Protein

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Aggregatin is a protein made of 452 amino acids.[7] It contains a domain of unknown function called pfam15258 which is 200 amino acids long.[7]

It has been found to be part of protein plaques formed in the brains of patients with Alzheimer's disease.[5]

 
This graph shows the changes in amino acid sequence that FAM222A has as a function of how related the organism is to humans. It is compared to other common genes.

FAM222A has an unusually high amount of prolines with a 6 segment run from amino acids 392 to 397.

Structurally, FAM222A has 5 domains which are connected by linker regions.[9][10]

Analysis of the amino acid sequence suggests that FAM222A is localized in the nucleus.[11]

Expression and regulation

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FAM222A is highly expressed in the brain and to a lesser extent in the adrenal glands.[8][12]

Alzheimer’s disease seems to cause an increase in FAM222A in the brain, but other degenerative diseases such as Parkinson’s do not.[13][14]

Interacting proteins

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FAM222A has been found to interact with mainly transcription factors. These include mainly  pre-B-cell leukemia transcription factors and Homeobox Meis proteins.[15]

Homologs

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FAM222A has only one paralog in humans, FAM222B which is also not well characterized.[16] These two proteins only share about 20% identity.

It has many orthologs in other organisms but is restricted to jawed vertebrates, as far back as bony and cartilaginous fish.[17] Overall the protein is well conserved with a lowest identity of around 50% but certain regions are very strictly conserved such as the beginning of pfam15258 as well as the last 60-70 amino acids on the C terminus.[6]

The protein appears to be changing very slowly even in distantly related animals. It is changing at a rate just slightly higher than Cytochrome C, a highly conserved protein.]

References

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  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000139438Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000041930Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ a b Yan T, Liang J, Gao J, Wang L, Fujioka H, Zhu X, Wang X (January 2020). "FAM222A encodes a protein which accumulates in plaques in Alzheimer's disease". Nature Communications. 11 (1): 411. Bibcode:2020NatCo..11..411Y. doi:10.1038/s41467-019-13962-0. PMC 6972869. PMID 31964863.
  6. ^ a b c d "FAM222A Gene - GeneCards | F222A Protein | F222A Antibody". www.genecards.org. Retrieved 2020-02-03.
  7. ^ a b c d e "FAM222A family with sequence similarity 222 member A [Homo sapiens (human)] - Gene - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2020-02-03.
  8. ^ a b c "GTEx Portal". gtexportal.org. Retrieved 2020-02-03.
  9. ^ "PHYRE2 Protein Fold Recognition Server". www.sbg.bio.ic.ac.uk. Retrieved 2020-04-29.
  10. ^ "I-TASSER server for protein structure and function prediction". zhanglab.ccmb.med.umich.edu. Retrieved 2020-04-29.
  11. ^ Reinhardt A, Hubbard T (May 1998). "Using neural networks for prediction of the subcellular location of proteins". Nucleic Acids Research. 26 (9): 2230–6. doi:10.1093/nar/26.9.2230. PMC 147531. PMID 9547285.
  12. ^ "Gene Detail :: Allen Brain Atlas: Mouse Brain". mouse.brain-map.org. Retrieved 2020-04-29.
  13. ^ "GDS4758 / 7958577". www.ncbi.nlm.nih.gov. Retrieved 2020-04-29.
  14. ^ "GDS3129 / 226487_at". www.ncbi.nlm.nih.gov. Retrieved 2020-04-29.
  15. ^ "FAM222A protein (human) - STRING interaction network". string-db.org. Retrieved 2020-04-29.
  16. ^ "FAM222B family with sequence similarity 222 member B [Homo sapiens (human)] - Gene - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2020-04-29.
  17. ^ "FAM222A orthologs". NCBI. Retrieved 2020-04-29.