DMPK
Miotonin-protein kinaza (MT-PK), znana i kao proteinska motonusna distrofijsk kinaza (MDPK) proteinska kinaza dystrophia myotonica (DMPK) je enzim koji je kod ljudi kodiran genom DMPK.[5][6][7]
Genski proizvod dmpk je Ser/Thr protein-kinaza homologna MRCK p21-aktiviranim kinazama i porodici Rho kinaza.[8] Podaci dobijeni korištenjem antitijela koja otkrivaju specifične izoforme DMPK ukazuju da je najzastupljenija izoforma DMPK protein od 80 kDa koji se eksprimira gotovo isključivo u glatkim, skeletnim i srčanim mišićima.[9] Ova kinaza postoji i kao membranski povezana i kao rastvorljiva forma u uzorcima ljudske lijeve komore. Različiti C-krajevi DMPK, koji nastaju alternativnom preradom, određuju njegovu lokalizaciju na endoplazmatski retikulum, mitohondrije ili citosol, u transficiranim COS-1 ćelijama.[10] Među supstratima za DMPK, koje su predložile studije in vitro, su fosfoleman, receptor za dihidropiridin i ciljna podjedinica miozin-fosfataze. Međutim, in vivo demonstriranje fosforilacije ovih supstrata, ostaje uspostavljena, ali njihova veza sa kliničkim manifestacijama miotonusne distrofije (DM) nije jasna.[11][12]
Struktura
[uredi | uredi izvor]Proteinska kinaza miotonusne distrofije (DMPK) je serin/treonin-kinaza koja se sastoji od domena kinaze i domena upredene zavojnice, uključene u multimerizaciju. Kristalna struktura kinaznog domena DMPK, vezana za inhibitor bisindolilmaleimid VIII (BIM-8), otkrila je dimerni enzim povezan sa konzerviranim domenom za dimerizaciju. Afinitet dimerizacije sugerirao je da sam kinazni domen nije dovoljan za dimerizaciju in vivo i da su domeni upredene zavojnice potrebn za stabilno stvaranje dimera. Domen kinaze je u aktivnoj konformaciji, s potpuno uređenom i pravilno postavljenom AC zavojnicom, a katalitski ostaci u konformaciji kompetentnoj za katalizu. Konzervirani hidrofobni motiv na produženom C-kraj kinaznog domena vezan je za N-terminalni režanj kinaznog domena, uprkos tome što je nefosforiliran.[13]
Aminokisekinska sekvenca
10 | 20 | 30 | 40 | 50 | ||||
---|---|---|---|---|---|---|---|---|
MSAEVRLRRL | QQLVLDPGFL | GLEPLLDLLL | GVHQELGASE | LAQDKYVADF | ||||
LQWAEPIVVR | LKEVRLQRDD | FEILKVIGRG | AFSEVAVVKM | KQTGQVYAMK | ||||
IMNKWDMLKR | GEVSCFREER | DVLVNGDRRW | ITQLHFAFQD | ENYLYLVMEY | ||||
YVGGDLLTLL | SKFGERIPAE | MARFYLAEIV | MAIDSVHRLG | YVHRDIKPDN | ||||
ILLDRCGHIR | LADFGSCLKL | RADGTVRSLV | AVGTPDYLSP | EILQAVGGGP | ||||
GTGSYGPECD | WWALGVFAYE | MFYGQTPFYA | DSTAETYGKI | VHYKEHLSLP | ||||
LVDEGVPEEA | RDFIQRLLCP | PETRLGRGGA | GDFRTHPFFF | GLDWDGLRDS | ||||
VPPFTPDFEG | ATDTCNFDLV | EDGLTAMVSG | GGETLSDIRE | GAPLGVHLPF | ||||
VGYSYSCMAL | RDSEVPGPTP | MELEAEQLLE | PHVQAPSLEP | SVSPQDETAE | ||||
VAVPAAVPAA | EAEAEVTLRE | LQEALEEEVL | TRQSLSREME | AIRTDNQNFA | ||||
SQLREAEARN | RDLEAHVRQL | QERMELLQAE | GATAVTGVPS | PRATDPPSHL | ||||
DGPPAVAVGQ | CPLVGPGPMH | RRHLLLPARV | PRPGLSEALS | LLLFAVVLSR | ||||
AAALGCIGLV | AHAGQLTAVW | RRPGAARAP |
- Simboli
C: Cistein
D: Asparaginska kiselina
E: Glutaminska kiselina
F: Fenilalanin
G: Glicin
H: Histidin
I: Izoleucin
K: Lizin
L: Leucin
M: Metionin
N: Asparagin
P: Prolin
Q: Glutamin
R: Arginin
S: Serin
T: Treonin
V: Valin
W: Triptofan
Y: Tirozin
Funkcija
[uredi | uredi izvor]Miotonin-protein kinaza je serin-treonin kinaza koja je usko povezana s drugim kinazama koje stupaju u interakciju s članovima porodice Rho malih GTPaza. Supstrati za ovaj enzim uključuju miogenin, beta-podjedinicu kalcijevog kanala L-tipa i fosfoleman.[7] Iako je specifična funkcija ovog proteina nepoznata, izgleda da ima važnu ulogu u mišićnim, srčanim i moždanim ćelijama. Ovaj protein može biti uključen u komunikaciju unutar ćelija. Čini se da regulira proizvodnju i funkciju važnih struktura unutar mišićnih ćelija, interakcijom s drugim proteinima. Naprimjer, dokazano je da protein-kinaza miotonusne didtrofije isključuje (inhibira) dio mišićnog proteina zvanog miozin-fosfataza. Miozi- fosfataza je enzim koji ima ulogu u grčenju (kontrakciji) i opuštanju mišića.[14]
Klinički značaj
[uredi | uredi izvor]The 3' untranslated region of this gene contains 5-37 copies of a CTG trinucleotide repeat. Expansion of this unstable motif to 50-5,000 copies causes myotonic dystrophy type I, which increases in severity with increasing repeat element copy number. Repeat expansion is associated with condensation of local chromatin structure that disrupts the expression of genes in this region. As the DMPK repeat is replicated, the hairpin loop that is formed leads to repeat expansion (a) or contractions (b).[7]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/d/d9/DMPK_CTG_Repeat.jpg/280px-DMPK_CTG_Repeat.jpg)
Miotonusna distrofija (DM) 1 je autosomno dominantni nervnomišići poremećaj koji pogapribližno 1/8.000 osoba. Pogođene osobe pokazuju širok spektar simptoma, uključujući miotoniju, slabost i gubitak skeletnih mišića, abnormalnosti srčanog provođenja i [[katarakt. Uprkos kloniranju lokusa, pokazalo se da je složeni fenotip bolesti DM teško interpretirati, a tačna uloga DMPK u patogenezi DM-a ostaje nejasna.[15]
Interakcije
[uredi | uredi izvor]Pokazalo se da protein kinaza miotonusne distrofije ima interakcija sa HSPB2[16][17] i RAC1.[18]
Regulacija
[uredi | uredi izvor]Bliska veza DMPK s Rho-kinazama dovela je do nagađanja može li se aktivnost DMPK in vivo regulirati malim G-proteinima, posebno iz porodice Rho. Iako DMPK nedostaju očigledna mesta vezanja za poznati G, oligomeri DMPK-1 pokazuju nisku baznu katalitsku aktivnost, zbog prisustva C-terminalnog autoinhibitornog domena (AI). Proteaza (P) unutar membrane cijepa DMPK-1 uklanjajući C-terminalni domen autoinhibitorne i membranske asocijacije, oslobađajući citosolni, u osnovi aktivni DMPK-2. Ovaj događaj obrade proizveo bi dugotrajnu aktivaciju kinaze. Kratkotrajna aktivacija DMPK-1 i -2 može biti posredovana privremenom interakcijom s malom GTPazom (G).
Predložen je opći model koji objašnjava oligomerizaciju, preradu i regulaciju DMPK. U ovom modelu, privremena aktivacija kinazne aktivnosti dogodila bi se kao odgovor na druge glasnike G-proteina, dok bi dugotrajna aktivacija DMPK mogla biti posredovana s membranom povezanom proteazom, koja cijepa DMPK-1, da bi oslobodio citosolni DMPK-2, u trajno aktiviranom obliku. Pokazalo se da uporna aktivacija serin / treonin kinaza ima ulogu u određivanju ćelijske sudbine, kao i stvaranju memorije u nervnom sistemu. U tom pogledu, DMPK može biti sličan PKA i PKC, dvije kinaze koje se mogu prolazno aktivirati, kao odgovor na druge glasnike ili uporno aktivirati proteolitskim uklanjanjem autoinhibitornog domena. Dakle, ovaj model sugerira da dva endogena oblika DMPK mogu imati različite aktivnosti, lokalizacije, regulatore i supstrate i obavljati različite fiziološke funkcije.[15][19]
Reference
[uredi | uredi izvor]- ^ a b c GRCh38: Ensembl release 89: ENSG00000104936 - Ensembl, maj 2017
- ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000030409 - Ensembl, maj 2017
- ^ "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.
- ^ Mahadevan M, Tsilfidis C, Sabourin L, Shutler G, Amemiya C, Jansen G, Neville C, Narang M, Barceló J, O'Hoy K (mart 1992). "Myotonic dystrophy mutation: an unstable CTG repeat in the 3' untranslated region of the gene". Science. 255 (5049): 1253–5. Bibcode:1992Sci...255.1253M. doi:10.1126/science.1546325. PMID 1546325.
- ^ Fu YH, Pizzuti A, Fenwick RG, King J, Rajnarayan S, Dunne PW, Dubel J, Nasser GA, Ashizawa T, de Jong P (mart 1992). "An unstable triplet repeat in a gene related to myotonic muscular dystrophy". Science. 255 (5049): 1256–8. Bibcode:1992Sci...255.1256F. doi:10.1126/science.1546326. PMID 1546326.
- ^ a b c "Entrez Gene: DMPK dystrophia myotonica-protein kinase".
- ^ Amano M, Chihara K, Nakamura N, Kaneko T, Matsuura Y, Kaibuchi K (novembar 1999). "The COOH terminus of Rho-kinase negatively regulates rho-kinase activity". The Journal of Biological Chemistry. 274 (45): 32418–24. doi:10.1074/jbc.274.45.32418. PMID 10542285.
- ^ Lam LT, Pham YC, Nguyen TM, Morris GE (septembar 2000). "Characterization of a monoclonal antibody panel shows that the myotonic dystrophy protein kinase, DMPK, is expressed almost exclusively in muscle and heart". Human Molecular Genetics. 9 (14): 2167–73. doi:10.1093/hmg/9.14.2167. PMID 10958655.
- ^ Wansink DG, van Herpen RE, Coerwinkel-Driessen MM, Groenen PJ, Hemmings BA, Wieringa B (august 2003). "Alternative splicing controls myotonic dystrophy protein kinase structure, enzymatic activity, and subcellular localization". Molecular and Cellular Biology. 23 (16): 5489–501. doi:10.1128/mcb.23.16.5489-5501.2003. PMC 166319. PMID 12897125.
- ^ Timchenko L, Nastainczyk W, Schneider T, Patel B, Hofmann F, Caskey CT (juni 1995). "Full-length myotonin protein kinase (72 kDa) displays serine kinase activity". Proceedings of the National Academy of Sciences of the United States of America. 92 (12): 5366–70. Bibcode:1995PNAS...92.5366T. doi:10.1073/pnas.92.12.5366. PMC 41695. PMID 7777513.
- ^ Kaliman P, Catalucci D, Lam JT, Kondo R, Gutiérrez JC, Reddy S, Palacín M, Zorzano A, Chien KR, Ruiz-Lozano P (mart 2005). "Myotonic dystrophy protein kinase phosphorylates phospholamban and regulates calcium uptake in cardiomyocyte sarcoplasmic reticulum". The Journal of Biological Chemistry. 280 (9): 8016–21. doi:10.1074/jbc.M412845200. PMID 15598648.
- ^ Elkins JM, Amos A, Niesen FH, Pike AC, Fedorov O, Knapp S (april 2009). "Structure of dystrophia myotonica protein kinase". Protein Science. 18 (4): 782–91. doi:10.1002/pro.82. PMC 2762590. PMID 19309729.
- ^ "DMPK gene". National Institutes of Health.
- ^ a b Bush EW, Helmke SM, Birnbaum RA, Perryman MB (juli 2000). "Myotonic dystrophy protein kinase domains mediate localization, oligomerization, novel catalytic activity, and autoinhibition". Biochemistry. 39 (29): 8480–90. doi:10.1021/bi992142f. PMID 10913253.
- ^ Suzuki A, Sugiyama Y, Hayashi Y, Nyu-i N, Yoshida M, Nonaka I, Ishiura S, Arahata K, Ohno S (mart 1998). "MKBP, a novel member of the small heat shock protein family, binds and activates the myotonic dystrophy protein kinase". The Journal of Cell Biology. 140 (5): 1113–24. doi:10.1083/jcb.140.5.1113. PMC 2132705. PMID 9490724.
- ^ Sugiyama Y, Suzuki A, Kishikawa M, Akutsu R, Hirose T, Waye MM, Tsui SK, Yoshida S, Ohno S (januar 2000). "Muscle develops a specific form of small heat shock protein complex composed of MKBP/HSPB2 and HSPB3 during myogenic differentiation". The Journal of Biological Chemistry. 275 (2): 1095–104. doi:10.1074/jbc.275.2.1095. PMID 10625651.
- ^ Shimizu M, Wang W, Walch ET, Dunne PW, Epstein HF (juni 2000). "Rac-1 and Raf-1 kinases, components of distinct signaling pathways, activate myotonic dystrophy protein kinase". FEBS Letters. 475 (3): 273–7. doi:10.1016/S0014-5793(00)01692-6. PMID 10869570. S2CID 46238883.
- ^ Edlund T, Jessell TM (januar 1999). "Progression from extrinsic to intrinsic signaling in cell fate specification: a view from the nervous system". Cell. 96 (2): 211–24. doi:10.1016/s0092-8674(00)80561-9. PMID 9988216. S2CID 15113604.
Dopunska literatura
[uredi | uredi izvor]- Groenen P, Wieringa B (novembar 1998). "Expanding complexity in myotonic dystrophy". BioEssays. 20 (11): 901–12. doi:10.1002/(SICI)1521-1878(199811)20:11<901::AID-BIES5>3.0.CO;2-0. PMID 9872056.
- Jansen G, Mahadevan M, Amemiya C, Wormskamp N, Segers B, Hendriks W, O'Hoy K, Baird S, Sabourin L, Lennon G (juli 1992). "Characterization of the myotonic dystrophy region predicts multiple protein isoform-encoding mRNAs". Nature Genetics. 1 (4): 261–6. doi:10.1038/ng0792-261. PMID 1302022. S2CID 26072532.
- Tsilfidis C, MacKenzie AE, Mettler G, Barceló J, Korneluk RG (juni 1992). "Correlation between CTG trinucleotide repeat length and frequency of severe congenital myotonic dystrophy". Nature Genetics. 1 (3): 192–5. doi:10.1038/ng0692-192. PMID 1303233. S2CID 24399657.
- Brook JD, McCurrach ME, Harley HG, Buckler AJ, Church D, Aburatani H, Hunter K, Stanton VP, Thirion JP, Hudson T (februar 1992). "Molecular basis of myotonic dystrophy: expansion of a trinucleotide (CTG) repeat at the 3' end of a transcript encoding a protein kinase family member". Cell. 68 (4): 799–808. doi:10.1016/0092-8674(92)90154-5. PMID 1310900. S2CID 19296009.
- Harley HG, Walsh KV, Rundle S, Brook JD, Sarfarazi M, Koch MC, Floyd JL, Harper PS, Shaw DJ (maj 1991). "Localisation of the myotonic dystrophy locus to 19q13.2-19q13.3 and its relationship to twelve polymorphic loci on 19q". Human Genetics. 87 (1): 73–80. doi:10.1007/BF01213096. PMID 2037285. S2CID 31229908.
- Gennarelli M, Lucarelli M, Zelano G, Pizzuti A, Novelli G, Dallapiccola B (novembar 1995). "Different expression of the myotonin protein kinase gene in discrete areas of human brain". Biochemical and Biophysical Research Communications. 216 (2): 489–94. doi:10.1006/bbrc.1995.2649. PMID 7488138.
- Shaw DJ, McCurrach M, Rundle SA, Harley HG, Crow SR, Sohn R, Thirion JP, Hamshere MG, Buckler AJ, Harper PS (decembar 1993). "Genomic organization and transcriptional units at the myotonic dystrophy locus". Genomics. 18 (3): 673–9. doi:10.1016/S0888-7543(05)80372-6. PMID 7905855.
- Sasagawa N, Sorimachi H, Maruyama K, Arahata K, Ishiura S, Suzuki K (august 1994). "Expression of a novel human myotonin protein kinase (MtPK) cDNA clone which encodes a protein with a thymopoietin-like domain in COS cells". FEBS Letters. 351 (1): 22–6. doi:10.1016/0014-5793(94)00808-6. PMID 8076686. S2CID 30863317.
- van der Ven PF, Jansen G, van Kuppevelt TH, Perryman MB, Lupa M, Dunne PW, ter Laak HJ, Jap PH, Veerkamp JH, Epstein HF (novembar 1993). "Myotonic dystrophy kinase is a component of neuromuscular junctions". Human Molecular Genetics. 2 (11): 1889–94. doi:10.1093/hmg/2.11.1889. PMID 8281152.
- Carango P, Noble JE, Marks HG, Funanage VL (novembar 1993). "Absence of myotonic dystrophy protein kinase (DMPK) mRNA as a result of a triplet repeat expansion in myotonic dystrophy". Genomics. 18 (2): 340–8. doi:10.1006/geno.1993.1474. PMID 8288237.
- Jansen G, Bartolomei M, Kalscheuer V, Merkx G, Wormskamp N, Mariman E, Smeets D, Ropers HH, Wieringa B (august 1993). "No imprinting involved in the expression of DM-kinase mRNAs in mouse and human tissues". Human Molecular Genetics. 2 (8): 1221–7. doi:10.1093/hmg/2.8.1221. PMID 8401505.
- Fu YH, Friedman DL, Richards S, Pearlman JA, Gibbs RA, Pizzuti A, Ashizawa T, Perryman MB, Scarlato G, Fenwick RG (april 1993). "Decreased expression of myotonin-protein kinase messenger RNA and protein in adult form of myotonic dystrophy". Science. 260 (5105): 235–8. Bibcode:1993Sci...260..235F. doi:10.1126/science.8469976. PMID 8469976.
- Mahadevan MS, Amemiya C, Jansen G, Sabourin L, Baird S, Neville CE, Wormskamp N, Segers B, Batzer M, Lamerdin J (mart 1993). "Structure and genomic sequence of the myotonic dystrophy (DM kinase) gene". Human Molecular Genetics. 2 (3): 299–304. doi:10.1093/hmg/2.3.299. PMID 8499920.
- Boucher CA, King SK, Carey N, Krahe R, Winchester CL, Rahman S, Creavin T, Meghji P, Bailey ME, Chartier FL (oktobar 1995). "A novel homeodomain-encoding gene is associated with a large CpG island interrupted by the myotonic dystrophy unstable (CTG)n repeat". Human Molecular Genetics. 4 (10): 1919–25. doi:10.1093/hmg/4.10.1919. PMID 8595416.
- Roberts R, Timchenko NA, Miller JW, Reddy S, Caskey CT, Swanson MS, Timchenko LT (novembar 1997). "Altered phosphorylation and intracellular distribution of a (CUG)n triplet repeat RNA-binding protein in patients with myotonic dystrophy and in myotonin protein kinase knockout mice". Proceedings of the National Academy of Sciences of the United States of America. 94 (24): 13221–6. Bibcode:1997PNAS...9413221R. doi:10.1073/pnas.94.24.13221. PMC 24290. PMID 9371827.
- Suzuki A, Sugiyama Y, Hayashi Y, Nyu-i N, Yoshida M, Nonaka I, Ishiura S, Arahata K, Ohno S (mart 1998). "MKBP, a novel member of the small heat shock protein family, binds and activates the myotonic dystrophy protein kinase". The Journal of Cell Biology. 140 (5): 1113–24. doi:10.1083/jcb.140.5.1113. PMC 2132705. PMID 9490724.
- Pham YC, Man N, Lam LT, Morris GE (novembar 1998). "Localization of myotonic dystrophy protein kinase in human and rabbit tissues using a new panel of monoclonal antibodies". Human Molecular Genetics. 7 (12): 1957–65. doi:10.1093/hmg/7.12.1957. PMID 9811941.
Vanjski linkovi
[uredi | uredi izvor]