Desmoplakin exists as two predominant isoforms; the first, known as "DPII", has molecular weight 260.0 kDa (2272 amino acids) and the second, known as "DPI", has molecular weight 332.0 kDa (2871 amino acids).[4][5] These isoforms are identical except for the shorter rod domain in DPII. DPI is the predominant isoform expressed in cardiac muscle.[6] The DSP gene is located on chromosome 6p24.3, containing 24 exons and spanning approximately 45 kDa of genomic DNA.[7] Desmoplakin is a large desmosomal plaque protein that homodimerizes and adopts a dumbbell-shaped conformation.[7] The N-terminal globular head domain of desmoplakin is composed of a series of alpha helical bundles, and is required for both the localization to the desmosome and interaction with the N-terminal region of plakophilin 1 and plakoglobin as well as desmocollin and desmoglein.[8] This is further sub divided into a region called the "Plakin domain" made up of six spectrin repeat domains separated by SH3 domain.[9] A crystal structure of part of the plakin domain has been resolved,[10] while the entire plakin domain has been elucidated using small angle X-ray scattering which revealed a non-linear structure, an unexpected result considering spectrin repeats are observed in linear orientations.[11] The C-terminal region of desmoplakin is composed of three plakin repeat domains, termed A, B and C, which are essential for coalignment and binding of intermediate filaments.[8][12][13] Located at the most distal C-terminus of desmoplakin is a region rich in glycine–serine–arginine; it has been demonstrated that serinephosphorylation of this domain may modify desmoplakin-intermediate filamentinteractions.[14] In the mid-region of desmoplakin, a coiled-coil rod domain is responsible for homodimerization.[15]
Function
Desmosomes are intercellular junctions that tightly link adjacent cells. Desmoplakin is an obligate component of functional desmosomes that anchors intermediate filaments to desmosomal plaques. In cardiomyocytes, desmoplakin forms desmosomal plaques with the intermediate filamentdesmin, whereas in endothelial cellscytokeratin type intermediate filaments are recruited, and vimentin in arachnoid and follicular dendritic cell types.[15][16] Both types of intermediate filaments attach in a lateral fashion to desmoplakin to form the plaque.[17] In cardiac muscle, desmoplakin is localized to desmosomes in intercalated discs. Desmoplakin isoform DPI is highly expressed and is thought to play a role in both the assembly and stabilization of desmosomes; its role is critical, as desmoplakin knockout mice display embryonic lethality.[18] In mice overexpressing a C-terminal mutated desmoplakin protein, desmoplakin binding to desmin is disrupted in cardiac muscle and hearts display abnormal intercalated disc formation and structure.[19] Much has been learned regarding desmoplakin function from mutations in patients with arrhythmogenic right ventricular cardiomyopathy, where mutations in specific binding domains alter desmoplakin binding to plakoglobin or desmin and result in cell death and dysfunction.[20]
↑ 7.07.1Green KJ, Parry DA, Steinert PM, Virata ML, Wagner RM, Angst BD, Nilles LA (Feb 1990). "Structure of the human desmoplakins. Implications for function in the desmosomal plaque". The Journal of Biological Chemistry. 265 (5): 2603–12. PMID1689290.
↑ 11.011.1Al-Jassar C, Knowles T, Jeeves M, Kami K, Behr E, Bikker H, Overduin M, Chidgey M (2011). "The nonlinear structure of the desmoplakin plakin domain and the effects of cardiomyopathy-linked mutations". J. Mol. Biol. 411 (5): 1049–61. doi:10.1016/j.jmb.2011.06.047. PMID21756917.
↑Choi HJ, Park-Snyder S, Pascoe LT, Green KJ, Weis WI (Aug 2002). "Structures of two intermediate filament-binding fragments of desmoplakin reveal a unique repeat motif structure". Nature Structural Biology. 9 (8): 612–20. doi:10.1038/nsb818. PMID12101406.
↑Stappenbeck TS, Lamb JA, Corcoran CM, Green KJ (Nov 1994). "Phosphorylation of the desmoplakin COOH terminus negatively regulates its interaction with keratin intermediate filament networks". The Journal of Biological Chemistry. 269 (47): 29351–4. PMID7525582.
↑ 19.019.1Yang Z, Bowles NE, Scherer SE, Taylor MD, Kearney DL, Ge S, Nadvoretskiy VV, DeFreitas G, Carabello B, Brandon LI, Godsel LM, Green KJ, Saffitz JE, Li H, Danieli GA, Calkins H, Marcus F, Towbin JA (Sep 2006). "Desmosomal dysfunction due to mutations in desmoplakin causes arrhythmogenic right ventricular dysplasia/cardiomyopathy". Circulation Research. 99 (6): 646–55. doi:10.1161/01.RES.0000241482.19382.c6. PMID16917092.
↑ 21.021.1Norgett EE, Hatsell SJ, Carvajal-Huerta L, Cabezas JC, Common J, Purkis PE, Whittock N, Leigh IM, Stevens HP, Kelsell DP (Nov 2000). "Recessive mutation in desmoplakin disrupts desmoplakin-intermediate filament interactions and causes dilated cardiomyopathy, woolly hair and keratoderma". Human Molecular Genetics. 9 (18): 2761–6. doi:10.1093/hmg/9.18.2761. PMID11063735.
↑Carvajal-Huerta L (Sep 1998). "Epidermolytic palmoplantar keratoderma with woolly hair and dilated cardiomyopathy". Journal of the American Academy of Dermatology. 39 (3): 418–21. doi:10.1016/s0190-9622(98)70317-2. PMID9738775.
↑Alcalai R, Metzger S, Rosenheck S, Meiner V, Chajek-Shaul T (Jul 2003). "A recessive mutation in desmoplakin causes arrhythmogenic right ventricular dysplasia, skin disorder, and woolly hair". Journal of the American College of Cardiology. 42 (2): 319–27. doi:10.1016/s0735-1097(03)00628-4. PMID12875771.
↑van der Zwaag PA, Jongbloed JD, van den Berg MP, van der Smagt JJ, Jongbloed R, Bikker H, Hofstra RM, van Tintelen JP (Sep 2009). "A genetic variants database for arrhythmogenic right ventricular dysplasia/cardiomyopathy". Human Mutation. 30 (9): 1278–83. doi:10.1002/humu.21064. PMID19569224.
↑Armstrong DK, McKenna KE, Purkis PE, Green KJ, Eady RA, Leigh IM, Hughes AE (Jan 1999). "Haploinsufficiency of desmoplakin causes a striate subtype of palmoplantar keratoderma". Human Molecular Genetics. 8 (1): 143–8. doi:10.1093/hmg/8.1.143. PMID9887343.
↑Whittock NV, Ashton GH, Dopping-Hepenstal PJ, Gratian MJ, Keane FM, Eady RA, McGrath JA (Dec 1999). "Striate palmoplantar keratoderma resulting from desmoplakin haploinsufficiency". The Journal of Investigative Dermatology. 113 (6): 940–6. doi:10.1046/j.1523-1747.1999.00783.x. PMID10594734.
↑Whittock NV, Wan H, Morley SM, Garzon MC, Kristal L, Hyde P, McLean WH, Pulkkinen L, Uitto J, Christiano AM, Eady RA, McGrath JA (Feb 2002). "Compound heterozygosity for non-sense and mis-sense mutations in desmoplakin underlies skin fragility/woolly hair syndrome". The Journal of Investigative Dermatology. 118 (2): 232–8. doi:10.1046/j.0022-202x.2001.01664.x. PMID11841538.
↑Carvajal-Huerta L (Sep 1998). "Epidermolytic palmoplantar keratoderma with woolly hair and dilated cardiomyopathy". Journal of the American Academy of Dermatology. 39 (3): 418–21. doi:10.1016/s0190-9622(98)70317-2. PMID9738775.
↑Anhalt GJ, Kim SC, Stanley JR, Korman NJ, Jabs DA, Kory M, Izumi H, Ratrie H, Mutasim D, Ariss-Abdo L (Dec 1990). "Paraneoplastic pemphigus. An autoimmune mucocutaneous disease associated with neoplasia". The New England Journal of Medicine. 323 (25): 1729–35. doi:10.1056/NEJM199012203232503. PMID2247105.
↑Papagerakis S, Shabana AH, Pollock BH, Papagerakis P, Depondt J, Berdal A (Sep 2009). "Altered desmoplakin expression at transcriptional and protein levels provides prognostic information in human oropharyngeal cancer". Human Pathology. 40 (9): 1320–9. doi:10.1016/j.humpath.2009.02.002. PMID19386346.
↑ 37.037.137.2Meng JJ, Bornslaeger EA, Green KJ, Steinert PM, Ip W (August 1997). "Two-hybrid analysis reveals fundamental differences in direct interactions between desmoplakin and cell type-specific intermediate filaments". J. Biol. Chem. 272 (34): 21495–503. doi:10.1074/jbc.272.34.21495. PMID9261168.
↑Hofmann I, Mertens C, Brettel M, Nimmrich V, Schnölzer M, Herrmann H (July 2000). "Interaction of plakophilins with desmoplakin and intermediate filament proteins: an in vitro analysis". J. Cell Sci. 113 (13): 2471–83. PMID10852826.
↑Chen X, Bonne S, Hatzfeld M, van Roy F, Green KJ (March 2002). "Protein binding and functional characterization of plakophilin 2. Evidence for its diverse roles in desmosomes and beta -catenin signaling". J. Biol. Chem. 277 (12): 10512–22. doi:10.1074/jbc.M108765200. PMID11790773.
↑Kowalczyk AP, Navarro P, Dejana E, Bornslaeger EA, Green KJ, Kopp DS, Borgwardt JE (October 1998). "VE-cadherin and desmoplakin are assembled into dermal microvascular endothelial intercellular junctions: a pivotal role for plakoglobin in the recruitment of desmoplakin to intercellular junctions". J. Cell Sci. 111 (20): 3045–57. PMID9739078.
Presland RB, Dale BA (2000). "Epithelial structural proteins of the skin and oral cavity: function in health and disease". Crit. Rev. Oral Biol. Med. 11 (4): 383–408. doi:10.1177/10454411000110040101. PMID11132762.
Just M, Herbst H, Hummel M, Dürkop H, Tripier D, Stein H, Schuppan D (1991). "Undulin is a novel member of the fibronectin-tenascin family of extracellular matrix glycoproteins". J. Biol. Chem. 266 (26): 17326–32. PMID1716629.
Green KJ, Parry DA, Steinert PM, Virata ML, Wagner RM, Angst BD, Nilles LA (1990). "Structure of the human desmoplakins. Implications for function in the desmosomal plaque". J. Biol. Chem. 265 (19): 11406–7. PMID2391353.
Steinert PM, Marekov LN (1997). "Direct evidence that involucrin is a major early isopeptide cross-linked component of the keratinocyte cornified cell envelope". J. Biol. Chem. 272 (3): 2021–30. doi:10.1074/jbc.272.3.2021. PMID8999895.
Olavesen MG, Bentley E, Mason RV, Stephens RJ, Ragoussis J (1997). "Fine mapping of 39 ESTs on human chromosome 6p23-p25". Genomics. 46 (2): 303–6. doi:10.1006/geno.1997.5032. PMID9417921.
Marekov LN, Steinert PM (1998). "Ceramides are bound to structural proteins of the human foreskin epidermal cornified cell envelope". J. Biol. Chem. 273 (28): 17763–70. doi:10.1074/jbc.273.28.17763. PMID9651377.
Suzuki M, Okuyama S, Okamoto S, Shirasuna K, Nakajima T, Hachiya T, Nojima H, Sekiya S, Oda K (1998). "A novel E2F binding protein with Myc-type HLH motif stimulates E2F-dependent transcription by forming a heterodimer". Oncogene. 17 (7): 853–65. doi:10.1038/sj.onc.1202163. PMID9780002.