| Structural highlights
Disease
HTRA2_HUMAN Defects in HTRA2 are the cause of Parkinson disease type 13 (PARK13) [MIM:610297. A complex neurodegenerative disorder characterized by bradykinesia, resting tremor, muscular rigidity and postural instability, as well as by a clinically significant response to treatment with levodopa. The pathology involves the loss of dopaminergic neurons in the substantia nigra and the presence of Lewy bodies (intraneuronal accumulations of aggregated proteins), in surviving neurons in various areas of the brain.[1] [2]
Function
HTRA2_HUMAN Serine protease that shows proteolytic activity against a non-specific substrate beta-casein. Promotes or induces cell death either by direct binding to and inhibition of BIRC proteins (also called inhibitor of apoptosis proteins, IAPs), leading to an increase in caspase activity, or by a BIRC inhibition-independent, caspase-independent and serine protease activity-dependent mechanism. Cleaves THAP5 and promotes its degradation during apoptosis. Isoform 2 seems to be proteolytically inactive.[3] [4]
Publication Abstract from PubMed
HtrA2 (high-temperature requirement 2) is a human mitochondrial protease that has a role in apoptosis and Parkinson's disease. The structure of HtrA2 with an intact catalytic triad was determined, revealing a conformational change in the active site loops, involving mainly the regulatory LD loop, which resulted in burial of the catalytic serine relative to the previously reported structure of the proteolytically inactive mutant. Mutations in the loops surrounding the active site that significantly restricted their mobility, reduced proteolytic activity both in vitro and in cells, suggesting that regulation of HtrA2 activity cannot be explained by a simple transition to an activated conformational state with enhanced active site accessibility. Manipulation of solvent viscosity highlighted an unusual bi-phasic behavior of the enzymatic activity, which together with MD calculations supports the importance of motion in the regulation of the activity of HtrA2. HtrA2 is an unusually thermostable enzyme (TM=97.3 degrees C), a trait often associated with structural rigidity, not dynamic motion. We suggest that this thermostability functions to provide a stable scaffold for the observed loop motions, allowing them a relatively free conformational search within a rather restricted volume.
Molecular motion regulates the activity of the Mitochondrial Serine Protease HtrA2.,Merski M, Moreira C, Abreu RM, Ramos MJ, Fernandes PA, Martins LM, Pereira PJB, Macedo-Ribeiro S Cell Death Dis. 2017 Oct 12;8(10):e3119. doi: 10.1038/cddis.2017.487. PMID:29022916[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Strauss KM, Martins LM, Plun-Favreau H, Marx FP, Kautzmann S, Berg D, Gasser T, Wszolek Z, Muller T, Bornemann A, Wolburg H, Downward J, Riess O, Schulz JB, Kruger R. Loss of function mutations in the gene encoding Omi/HtrA2 in Parkinson's disease. Hum Mol Genet. 2005 Aug 1;14(15):2099-111. Epub 2005 Jun 16. PMID:15961413 doi:10.1093/hmg/ddi215
- ↑ Bogaerts V, Nuytemans K, Reumers J, Pals P, Engelborghs S, Pickut B, Corsmit E, Peeters K, Schymkowitz J, De Deyn PP, Cras P, Rousseau F, Theuns J, Van Broeckhoven C. Genetic variability in the mitochondrial serine protease HTRA2 contributes to risk for Parkinson disease. Hum Mutat. 2008 Jun;29(6):832-40. PMID:18401856 doi:10.1002/humu.20713
- ↑ Bartke T, Pohl C, Pyrowolakis G, Jentsch S. Dual role of BRUCE as an antiapoptotic IAP and a chimeric E2/E3 ubiquitin ligase. Mol Cell. 2004 Jun 18;14(6):801-11. PMID:15200957 doi:10.1016/j.molcel.2004.05.018
- ↑ Balakrishnan MP, Cilenti L, Mashak Z, Popat P, Alnemri ES, Zervos AS. THAP5 is a human cardiac-specific inhibitor of cell cycle that is cleaved by the proapoptotic Omi/HtrA2 protease during cell death. Am J Physiol Heart Circ Physiol. 2009 Aug;297(2):H643-53. doi:, 10.1152/ajpheart.00234.2009. Epub 2009 Jun 5. PMID:19502560 doi:10.1152/ajpheart.00234.2009
- ↑ Merski M, Moreira C, Abreu RM, Ramos MJ, Fernandes PA, Martins LM, Pereira PJB, Macedo-Ribeiro S. Molecular motion regulates the activity of the Mitochondrial Serine Protease HtrA2. Cell Death Dis. 2017 Oct 12;8(10):e3119. doi: 10.1038/cddis.2017.487. PMID:29022916 doi:http://dx.doi.org/10.1038/cddis.2017.487
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