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From Proteopedia
Cryo-EM structure of the R243C mutant of human Prolyl Endopeptidase-Like (PREPL) protein involved in Congenital myasthenic syndrome-22 (CMS22)
Structural highlights
DiseasePPCEL_HUMAN 2p21 microdeletion syndrome;Atypical hypotonia-cystinuria syndrome;2p21 microdeletion syndrome without cystinuria;Hypotonia-cystinuria syndrome. The gene represented in this entry is involved in disease pathogenesis. Hypotonia-cystinuria syndrome is a contiguous gene syndrome caused by a homozygous deletion on chromosome 2p21 that disrupts the gene represented in this entry and SLC3A1 (PubMed:16385448, PubMed:21686663). A homozygous 77.4-kb deletion that disrupts the gene represented in this entry, SLC3A1 and CAMKMT, causes atypical hypotonia-cystinuria syndrome, characterized by mild to moderate mental retardation and respiratory chain complex IV deficiency (PubMed:21686663). Patient cells exhibit a larger trans-Golgi network and a reduced redistribution of AP-1 complex, which causes impairment in AP-1 mediated membrane-cytoplasm recycling and secretion (PubMed:23321636).[1] [2] [3] The disease is caused by variants affecting the gene represented in this entry. FunctionPPCEL_HUMAN Serine peptidase whose precise substrate specificity remains unclear (PubMed:16143824, PubMed:16385448, PubMed:28726805). Does not cleave peptides after a arginine or lysine residue (PubMed:16143824). Regulates trans-Golgi network morphology and sorting by regulating the membrane binding of the AP-1 complex (PubMed:23321636). May play a role in the regulation of synaptic vesicle exocytosis (PubMed:24610330).[4] [5] [6] [7] [8] Publication Abstract from PubMedCongenital myasthenic syndrome-22 (CMS22, OMIM 616224) is a rare genetic disorder caused by deleterious genetic variation in the prolyl endopeptidase-like (PREPL) gene. Previous reports have described patients with deletions and nonsense variants in PREPL, but nothing is known about the effect of missense variants in the pathology of CMS22. In this study, we have functionally characterized missense variants in PREPL from three CMS22 patients, all with hallmark phenotypes. Biochemical evaluation revealed that these missense variants do not impair hydrolase activity, thereby challenging the conventional diagnostic criteria and disease mechanism. Structural analysis showed that the variants affect regions most likely involved in intra-protein or protein-protein interactions. Indeed, binding to a selected group of known interactors was differentially reduced for the three mutants. The importance of non-hydrolytic functions of PREPL was investigated in catalytically inactive PREPL p.Ser559Ala cell lines which showed that hydrolytic activity of PREPL is needed for normal mitochondrial function but not for regulating AP1-mediated transport in the trans-Golgi network. In conclusion, these studies showed that CMS22 can be caused not only by deletion and truncation of PREPL but also by missense variants that do not necessarily result in a loss of hydrolytic activity of PREPL. Missense variants in CMS22 patients reveal that PREPL has both enzymatic and non-enzymatic functions.,Monnens Y, Theodoropoulou A, Rosier K, Bhalla K, Mahy A, Vanhoutte R, Meulemans S, Cavani E, Antanasijevic A, Lemmens I, Lee JA, Spellicy CJ, Schroer RJ, Maselli RA, Laverty CG, Agostinis P, Pagliarini DJ, Verhelst S, Marcaida MJ, Rochtus A, Dal Peraro M, Creemers JW JCI Insight. 2024 Jul 30:e179276. doi: 10.1172/jci.insight.179276. PMID:39078710[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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