Glutamate decarboxylase like 1 (GADL1) is the enzyme responsible for decarboxylating aspartate (Asp) to β-alanine and cysteine sulfinic acid (CSA) to hypotaurine.[5] GADL1 is a Pyridoxal 5’-phosphate (PLP)-dependent enzyme. By decarboxylating Asp to β-alanine, GADL1 consequently plays a role in the production of carnosine.[6] Carnosine and taurine have multiple biological functions such as calcium regulation, pH buffering, metal chelation, and antioxidant effects. β-Alanine also plays a role as neurotransmitter or neuromodulator in the central nervous system (CNS) and olfactory bulbs.[7]

GADL1
Available structures
PDBOrtholog search: PDBe RCSB
Identifiers
AliasesGADL1, ADC, CSADC, HuADC, HuCSADC, glutamate decarboxylase like 1
External IDsOMIM: 615601; MGI: 1920998; HomoloGene: 45812; GeneCards: GADL1; OMA:GADL1 - orthologs
EC number4.1.1.29
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_207359

NM_028638

RefSeq (protein)

NP_997242

NP_082914
NP_001382689

Location (UCSC)Chr 3: 30.73 – 30.89 MbChr 9: 115.91 – 116.08 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

Homology with CSAD

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GADL1 has 61% homology with another PLP-dependent enzyme cysteine sulfinic acid decarboxylase (CSAD).[8] CSAD plays a role in taurine production by decarboxylating CSA to hypotaurine. Taurine is the most abundant amino acid in mammals and plays roles as an antioxidant, membrane stabilizer and neurotransmitter or neuromodulator in the CNS[9] and recently has received growing attention as a biomarker for different diseases.[10]

Tissue distribution

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In humans, both GADL1 and CSAD are expressed in the brain and neurons whereas only CSAD was found in the liver. In mice, both enzymes are expressed in the brain, olfactory bulbs, and skeletal muscle but only CSAD was found in the kidney and liver.

GADL1 is named ADC, CSADC, HuADC, HuCSADC in some papers.

Structure

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Both CSAD and GADL1 are homodimers. The structure of mouse GADL1 was published in 2018 with the PDB number 6ENZ [11] and the structure of mouse CSAD was published in 2021 with the PDB number 6ZEK.[12]

Therapeutic potential

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In 2014 a paper showed an association between GADL1 variants and bipolar patients' responses to lithium therapy.[13] Although these findings were not replicable, this article triggers more studies on GADL1. So far there has not been any paper published reporting reproducible data on the therapeutic role of GADL1. However, this novel PLP-dependent enzyme has a high potential for further investigation.

References

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  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000144644Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000056880Ensembl, 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. ^ Liu P, Ge X, Ding H, Jiang H, Christensen BM, Li J (November 2012). "Role of glutamate decarboxylase-like protein 1 (GADL1) in taurine biosynthesis". The Journal of Biological Chemistry. 287 (49): 40898–906. doi:10.1074/jbc.M112.393728. PMC 3510794. PMID 23038267.
  6. ^ Mahootchi E, Cannon Homaei S, Kleppe R, Winge I, Hegvik TA, Megias-Perez R, et al. (July 2020). "GADL1 is a multifunctional decarboxylase with tissue-specific roles in β-alanine and carnosine production". Science Advances. 6 (29): eabb3713. Bibcode:2020SciA....6.3713M. doi:10.1126/sciadv.abb3713. PMC 7367687. PMID 32733999.
  7. ^ Boldyrev AA, Aldini G, Derave W (October 2013). "Physiology and pathophysiology of carnosine". Physiological Reviews. 93 (4): 1803–45. doi:10.1152/physrev.00039.2012. PMID 24137022.
  8. ^ Winge I, Teigen K, Fossbakk A, Mahootchi E, Kleppe R, Sköldberg F, et al. (November 2015). "Mammalian CSAD and GADL1 have distinct biochemical properties and patterns of brain expression". Neurochemistry International. 90: 173–84. doi:10.1016/j.neuint.2015.08.013. hdl:1956/11730. PMID 26327310. S2CID 3797582.
  9. ^ Ripps H, Shen W (2012). "Review: taurine: a "very essential" amino acid". Molecular Vision. 18: 2673–86. PMC 3501277. PMID 23170060.
  10. ^ Samuelsson M, Gerdin G, Ollinger K, Vrethem M (June 2012). "Taurine and glutathione levels in plasma before and after ECT treatment". Psychiatry Research. 198 (1): 53–7. doi:10.1016/j.psychres.2012.02.016. PMID 22453189. S2CID 20146045.
  11. ^ Raasakka A, Mahootchi E, Winge I, Luan W, Kursula P, Haavik J (January 2018). "Structure of the mouse acidic amino acid decarboxylase GADL1". Acta Crystallographica. Section F, Structural Biology Communications. 74 (Pt 1): 65–73. Bibcode:2018AcCrF..74...65R. doi:10.1107/S2053230X17017848. PMC 5947694. PMID 29372909.
  12. ^ Mahootchi E, Raasakka A, Luan W, Muruganandam G, Loris R, Haavik J, et al. (March 2021). "Structure and substrate specificity determinants of the taurine biosynthetic enzyme cysteine sulphinic acid decarboxylase". Journal of Structural Biology. 213 (1): 107674. doi:10.1016/j.jsb.2020.107674. hdl:11250/2759264. PMID 33253877. S2CID 227245688.
  13. ^ Chen CH, Lee CS, Lee MT, Ouyang WC, Chen CC, Chong MY, et al. (January 2014). "Variant GADL1 and response to lithium therapy in bipolar I disorder". The New England Journal of Medicine. 370 (2): 119–28. doi:10.1056/NEJMoa1212444. PMID 24369049.