Adenylyl cyclase type 5 is anenzyme that in humans is encoded by theADCY5gene.[5][6]
The humanADCY5 gene is located on the long arm of chromosome 3 and codes for the enzyme Adenylyl Cyclase 5 (AC5). This membrane protein has catalytic activity to convertadenosine triphosphate (ATP) intocyclic adenosine monophosphate (cAMP). In the brain, this enzyme is highly expressed inmedium spiny neurons (MSNs) in thestriatum. It is also found in non-neuronal cells such as cardiomyocytes and pancreatic islets. AC5 plays a role in several physiological processes including the modulation of neuronal activity particularly in the striatum, thus variants inADCY5 gene typically lead tomovement disorders.
AC5 is a transmembrane protein with a cytoplasmic catalytic domain separated from the membrane by a coiled-coil stem which is part of its regulatory domain
AC5 is encoded by theADCY5 gene, located on the long arm of chromosome 3. The AC5 protein is composed of an intracytoplasmic N-terminal domain, a first membrane subdomain of 6 transmembrane segments, a first catalytic subdomain (C1a), a regulatory domain (C1b), a second membrane subdomain of 6 transmembrane segments, and a second catalytic subdomain (C2a). In contrast to otherACs, AC5 doesn't have a complete C-terminal regulatory domain (C2b). In the cytoplasm, the 2 catalytic subdomains associate to form the catalytic domain, binding ATP and converting it intocAMP. The 2 membrane subdomains are associated to form a single bundle in the plasmic membrane.[7] The transmembrane domain is prolonged by 2 cytoplasmic helices (H1 and H2) forming acoiled-coil domain which separates the core catalytic domain from the membrane. The conformation of the C1b regulatory and coiled-coil domains as well as their association with the various subunits of the G proteins change the dynamic conformation of the 2 catalytic subdomains and impact the catalytic activity of AC5. The N-terminal domain may participate in regulation by G proteins;[8][9] however, its structural organization is only partly solved.
The mammalianadenylyl cyclase family comprises nine membrane adenylyl cyclases (mACs, AC1-9), and one soluble adenylyl cyclase (sAC, AC10). As an adenylyl cyclase, AC5 catalyses the production of the second messengercAMP from ATP, under the regulation ofG proteins.[10][11] The level of cellularcAMP controls the activity ofprotein kinase A (PKA), which phosphorylates target proteins. Upon phosphorylation, these effectors allow the cellular response to stimulation ofG protein-coupled receptors (GPCR). However, AC5 differs from other mACs by its sequence and length, its expression pattern and its regulation.AC5 has been identified as the primaryAC isoform expressed inMSNs.[12] The striatum controls movement via a subtle balance between the activity of two types of MSNs: the striato-nigral MSNs of the direct pathway that facilitate movement execution and the striato-pallidal MSNs of the indirect pathway that inhibit movement execution. The synthesis ofcAMP by AC5 in MSNs is finely regulated byG protein-coupled receptors. AC5 is activated by the Gαolf protein (encoded by theGNAL gene) downstream of theD1 dopamine receptor (D1R) in the direct pathway and theadenosine A2A receptor (A2AR) in the indirect pathway, while it is inhibited by Gαi/o downstream of theD2 dopamine receptors (D2R) in the indirect pathway and theadenosine A1 receptor (A1R) in the direct pathway. cAMP levels in direct/indirect MSNs are critical for the activation of their target neurons, and thus facilitation or inhibition of movement.
AC5 is the key enzyme in the cAMP signalling pathway responding to dopamine and adenosine in MSNs
In MSNs, AC5 associates with the heterotrimeric protein G containingGαolf,Gβ2 andGγ7.[13] In vitro, AC5 can also interact withGβ1 andGγ2 through its N-terminal domain. AC5 has been shown tointeract withRGS2.[14]
ADCY5-related movement disorder is named after the causative geneADCY5, found in 2012 via wholeexome sequencing.[15] However, the first patient's description was made in 1967 as “paroxysmal choreoathetosis”.[16] This case and her family history were reappraised when her daughter started to have similar manifestations, then described as “familial dyskinesia with facial myokymia”.[17] This disease is presently referred to as MxMD-ADCY5 since the phenotypic spectrum has been more extensively studied.[18] Indeed, the clinical spectrum is very broad and is typically characterized by a variable combination of permanent and paroxysmal hyperkinetic movements such asmyoclonus,chorea,tremor and/ordystonia.[19] These symptoms can be more or less severe but, in most cases, hamper the quality of life of patients. The occurrence of paroxysmal nocturnaldyskinesias and the presence of perioral twitches are particularly suggestive of the diagnosis. These dyskinesias are sometimes associated with other symptoms such as axialhypotonia, speech disturbance, oculomotor signs,pyramidal syndrome, developmental delay,psychiatric disorders orintellectual disability.[20] Likewise, a few patients have been reported withheart failure, raising the possibility of cardiac involvement.[21]
Missense and small indels variants associated with MxMD-ADCY5 Dominant variant /Recessive variant
MxMD-ADCY5 is most often transmitted in anautosomal dominant manner and more rarely autosomal recessive.[22] The occurrence of somaticmosaicism[18] is unexpectedly frequent in MxMD-ADCY5, with a less severe phenotype.[19] The most described causal variant is the dominant mutation R418W situated in the coiled-coil domain of AC5. Most of the known variants are concentrated in the coiled-coil, catalytic (C1a and C2a) and regulatory (C1b) domains of AC5 suggesting a dysregulation of its enzymatic activity in patients.
The pathophysiology of this disease is based on a deregulation of the cAMP pathway in the striatum linked toADCY5 mutations, disrupting the balance between the direct and indirect pathways of movement control. In vitro functional studies have shown a gain of function for several dominant non-truncatingmutations altering cAMP production after G protein-coupled receptors stimulation compared to wildtype AC5.[23][24] The pathophysiology of truncating and/or recessive variants is poorly known.
ADCY5 seems to play a role in cardiac function and may be involved in bothlongevity andstress resistance. Indeed, mice with a complete depletion of ADCY5 live significantly longer than control littermates and are resistant to cardiac stress.[31][32][33]
^"Human PubMed Reference:".National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:".National Center for Biotechnology Information, U.S. National Library of Medicine.
^Raimundo S, Giray J, Volff JN, Schwab M, Altenbuchner J, Ratge D, et al. (July 1999). "Cloning and sequence of partial cDNAs encoding the human type V and VI adenylyl cyclases and subsequent RNA-quantification in various tissues".Clinica Chimica Acta; International Journal of Clinical Chemistry.285 (1–2):155–161.doi:10.1016/S0009-8981(99)00067-4.PMID10481931.
^Sanabra C, Mengod G (January 2011). "Neuroanatomical distribution and neurochemical characterization of cells expressing adenylyl cyclase isoforms in mouse and rat brain".Journal of Chemical Neuroanatomy.41 (1):43–54.doi:10.1016/j.jchemneu.2010.11.001.hdl:10261/73698.PMID21094251.
^Perez-Borja C, Tassinari AC, Swanson AG (December 1967). "Paroxysmal choreoathetosis and seizures induced by movement (reflex epilepsy)".Epilepsia.8 (4):260–270.doi:10.1111/j.1528-1157.1967.tb04442.x.PMID5238718.
^Fernandez M, Raskind W, Wolff J, Matsushita M, Yuen E, Graf W, et al. (April 2001). "Familial dyskinesia and facial myokymia (FDFM): a novel movement disorder".Annals of Neurology.49 (4):486–492.doi:10.1002/ana.98.PMID11310626.
^Bohlega SA, Abou-Al-Shaar H, AlDakheel A, Alajlan H, Bohlega BS, Meyer BF, et al. (July 2019). "Autosomal recessive ADCY5-Related dystonia and myoclonus: Expanding the genetic spectrum of ADCY5-Related movement disorders".Parkinsonism & Related Disorders.64:145–149.doi:10.1016/j.parkreldis.2019.02.039.PMID30975617.
^Méneret A, Mohammad SS, Cif L, Doummar D, DeGusmao C, Anheim M, et al. (June 2022). "Efficacy of Caffeine in ADCY5-Related Dyskinesia: A Retrospective Study".Movement Disorders.37 (6):1294–1298.doi:10.1002/mds.29006.PMID35384065.
^Kim KS, Kim H, Baek IS, Lee KW, Han PL (May 2011). "Mice lacking adenylyl cyclase type 5 (AC5) show increased ethanol consumption and reduced ethanol sensitivity".Psychopharmacology.215 (2):391–398.doi:10.1007/s00213-010-2143-x.PMID21193983.
^Kim H, Lee Y, Park JY, Kim JE, Kim TK, Choi J, et al. (December 2017). "Loss of Adenylyl Cyclase Type-5 in the Dorsal Striatum Produces Autistic-Like Behaviors".Molecular Neurobiology.54 (10):7994–8008.doi:10.1007/s12035-016-0256-x.PMID27878759.
Haber N, Stengel D, Defer N, Roeckel N, Mattei MG, Hanoune J (July 1994). "Chromosomal mapping of human adenylyl cyclase genes type III, type V and type VI".Human Genetics.94 (1):69–73.doi:10.1007/BF02272844.PMID8034296.S2CID6473135.
Barcova M, Speth C, Kacani L, Uberall F, Stoiber H, Dierich MP (March 1999). "Involvement of adenylate cyclase and p70(S6)-kinase activation in IL-10 up-regulation in human monocytes by gp41 envelope protein of human immunodeficiency virus type 1".Pflügers Archiv.437 (4):538–546.doi:10.1007/s004240050815.PMID10089566.S2CID7620262.
Ludwig MG, Seuwen K (2003). "Characterization of the human adenylyl cyclase gene family: cDNA, gene structure, and tissue distribution of the nine isoforms".Journal of Receptor and Signal Transduction Research.22 (1–4):79–110.doi:10.1081/RRS-120014589.PMID12503609.S2CID36697419.
1azs: COMPLEX OF GS-ALPHA WITH THE CATALYTIC DOMAINS OF MAMMALIAN ADENYLYL CYCLASE
1cjk: COMPLEX OF GS-ALPHA WITH THE CATALYTIC DOMAINS OF MAMMALIAN ADENYLYL CYCLASE: COMPLEX WITH ADENOSINE 5'-(ALPHA THIO)-TRIPHOSPHATE (RP), MG, AND MN
1cjt: COMPLEX OF GS-ALPHA WITH THE CATALYTIC DOMAINS OF MAMMALIAN ADENYLYL CYCLASE: COMPLEX WITH BETA-L-2',3'-DIDEOXYATP, MN, AND MG
1cju: COMPLEX OF GS-ALPHA WITH THE CATALYTIC DOMAINS OF MAMMALIAN ADENYLYL CYCLASE: COMPLEX WITH BETA-L-2',3'-DIDEOXYATP AND MG
1cjv: COMPLEX OF GS-ALPHA WITH THE CATALYTIC DOMAINS OF MAMMALIAN ADENYLYL CYCLASE: COMPLEX WITH BETA-L-2',3'-DIDEOXYATP, MG, AND ZN
1cs4: COMPLEX OF GS-ALPHA WITH THE CATALYTIC DOMAINS OF MAMMALIAN ADENYLYL CYCLASE: COMPLEX WITH 2'-DEOXY-ADENOSINE 3'-MONOPHOSPHATE, PYROPHOSPHATE AND MG
1cul: COMPLEX OF GS-ALPHA WITH THE CATALYTIC DOMAINS OF MAMMALIAN ADENYLYL CYCLASE: COMPLEX WITH 2',5'-DIDEOXY-ADENOSINE 3'-TRIPHOSPHATE AND MG
1tl7: Complex Of Gs- With The Catalytic Domains Of Mammalian Adenylyl Cyclase: Complex With 2'(3')-O-(N-methylanthraniloyl)-guanosine 5'-triphosphate and Mn
1u0h: STRUCTURAL BASIS FOR THE INHIBITION OF MAMMALIAN ADENYLYL CYCLASE BY MANT-GTP
2gvd: Complex Of Gs- With The Catalytic Domains Of Mammalian Adenylyl Cyclase: Complex With TNP-ATP and Mn
2gvz: Crystal Structure of Complex of Gs- with The Catalytic Domains of Mammalian Adenylyl Cyclase: Complex with MANT-ATP and Mn