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Ichhaporia VP, Hendershot LM. Role of the HSP70 Co-Chaperone SIL1 in Health and Disease. Int J Mol Sci 2021; 22:ijms22041564. [PMID: 33557244 PMCID: PMC7913895 DOI: 10.3390/ijms22041564] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 01/30/2021] [Accepted: 01/30/2021] [Indexed: 12/04/2022] Open
Abstract
Cell surface and secreted proteins provide essential functions for multicellular life. They enter the endoplasmic reticulum (ER) lumen co-translationally, where they mature and fold into their complex three-dimensional structures. The ER is populated with a host of molecular chaperones, associated co-factors, and enzymes that assist and stabilize folded states. Together, they ensure that nascent proteins mature properly or, if this process fails, target them for degradation. BiP, the ER HSP70 chaperone, interacts with unfolded client proteins in a nucleotide-dependent manner, which is tightly regulated by eight DnaJ-type proteins and two nucleotide exchange factors (NEFs), SIL1 and GRP170. Loss of SIL1′s function is the leading cause of Marinesco-Sjögren syndrome (MSS), an autosomal recessive, multisystem disorder. The development of animal models has provided insights into SIL1′s functions and MSS-associated pathologies. This review provides an in-depth update on the current understanding of the molecular mechanisms underlying SIL1′s NEF activity and its role in maintaining ER homeostasis and normal physiology. A precise understanding of the underlying molecular mechanisms associated with the loss of SIL1 may allow for the development of new pharmacological approaches to treat MSS.
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Arabadzhiev TI, Dimitrov GV, Chakarov VE, Dimitrov AG, Dimitrova NA. Effects of changes in intracellular action potential on potentials recorded by single-fiber, macro, and belly-tendon electrodes. Muscle Nerve 2008; 37:700-12. [PMID: 18506714 DOI: 10.1002/mus.21024] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Some myopathies are accompanied by abnormal calcium homeostasis. Electromyography (EMG) in such patients shows signs of normal or myopathic EMG when detected by a single-fiber electrode and abnormally increased values in macro EMG. As calcium accumulation might be accompanied by changes in intracellular action potential (IAP) and muscle-fiber propagation velocity, we simulated the effects of such changes on motor unit potentials (MUPs) recorded by different kinds of electrodes. We found that: (1) the requirements for what potential can be accepted as a single-fiber action potential (SFAP) are too rigorous; (2) macro MUP amplitude can increase while SFAP amplitude can decrease when there is an increase in the spatial length of IAP spike; and (3) changes in the second phase of a belly-tendon-detected MUP or M wave could be used for noninvasive detection of increased IAP depolarizing (negative) after-potential.
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Affiliation(s)
- Todor I Arabadzhiev
- Centre of Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 105, Sofia 1113, Bulgaria.
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Arabadzhiev TI, Dimitrov GV, Chakarov VE, Dimitrov AG, Dimitrova NA. Changes in intracellular action potential profile affect parameters used in turns/amplitude analysis. Muscle Nerve 2008; 37:713-20. [PMID: 18506716 DOI: 10.1002/mus.21022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The influence of changes in the intracellular action potential (IAP) spatial profile on motor unit potentials (MUPs), number of turns per second (NTs), and mean turn amplitude were simulated and analyzed. We show why measurement of NTs was "the best indicator of neurogenic affection" and why the lower diagnostic yield of turns/amplitude analysis in myopathy could be due to changes in IAP shape caused by elevated free calcium concentration. The results explain the complications observed when interference electromyographic signals obtained during high levels of isometric contractions were analyzed. We show that, in contrast to earlier assumptions, the effect of increased IAP spike duration on NTs was stronger than that of a decrease in muscle fiber propagation velocity (MFPV). The decrease in the NTs could occur without a drop-out of MUs and/or a decrease in their firing rates, and without a change in MFPV and synchronous firing.
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Affiliation(s)
- Todor I Arabadzhiev
- Centre of Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 105, Sofia 1113, Bulgaria.
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Arabadzhiev T, Dimitrov G, Dimitrov A, Chakarov V, Dimitrova N. Factors affecting the turns analysis of the interference EMG signal. Biomed Signal Process Control 2008. [DOI: 10.1016/j.bspc.2007.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Mahjneh I, Anttonen AK, Somer M, Paetau A, Lehesjoki AE, Somer H, Udd B. Myopathy is a prominent feature in Marinesco-Sjögren syndrome: A muscle computed tomography study. J Neurol 2005; 253:301-6. [PMID: 16151599 DOI: 10.1007/s00415-005-0983-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Revised: 06/19/2005] [Accepted: 07/05/2005] [Indexed: 12/15/2022]
Abstract
BACKGROUND Marinesco-Sjögren syndrome (MSS) is an autosomal recessive multiorgan disorder showing clinical and genetic heterogeneity. The key features of MSS include cerebellar ataxia, early bilateral cataracts, delayed motor development, and varying degrees of mental retardation. Patients with a subtype of MSS with myoglobinuria and neuropathy have been linked to chromosome 18qter, and recently a locus for classical MSS has been localized on chromosome 5q31. OBJECTIVES To determine the importance of myopathy in this disorder apart from the CNS based disability and to establish the pattern of muscle involvement and degree of its severity. METHODS Muscle computed tomography (CT) investigations were carried out in nine Finnish MSS patients homozygous for markers around the MSS locus on chromosome 5q31. RESULTS Patients with severe clinical disability showed severe and generalized muscle degeneration. Muscle CT findings in patients with relatively severe clinical picture were characterized by severe involvement of the posterior thoracic and pelvic muscles, and almost all thigh muscles. In the legs the peronei and posterior compartment muscles were severely degenerated. The group of patients with moderate severity of disease showed the same pattern of involved muscle, albeit with lower degree of muscle degeneration. CONCLUSIONS Patients with MSS linked to chromosome 5q31 have a severe progressive myopathy, the extent of which may remain largely unrecognized because of the CNS involvement.
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Affiliation(s)
- Ibrahim Mahjneh
- Dept. of Neurology, Pietasaari Hospital PL 23, 68601 Pietasaari, Finland.
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Lagier-Tourenne C, Tranebaerg L, Chaigne D, Gribaa M, Dollfus H, Silvestri G, Bétard C, Warter JM, Koenig M. Homozygosity mapping of Marinesco-Sjögren syndrome to 5q31. Eur J Hum Genet 2004; 11:770-8. [PMID: 14512967 DOI: 10.1038/sj.ejhg.5201068] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Marinesco-Sjögren syndrome (MSS), first described in 1931, is an autosomal recessive condition characterised by somatic and mental retardation, congenital cataracts and cerebellar ataxia. Progressive myopathy was later reported to be also a cardinal sign of MSS, with myopathic changes on muscle biopsies. Hypergonadotrophic hypogonadism and skeletal deformities related to pronounced hypotonia were also reported. The major differential diagnosis of MSS is the syndrome defined by congenital cataracts, facial dysmorphism and peripheral neuropathy (CCFDN), which is localised to 18qter. Using homozygosity mapping strategy in two large consanguineous families of Turkish and Norwegian origin, respectively, we have identified the MSS locus on chromosome 5q31. LOD score calculation, including the consanguinity loops, gave a maximum value of 2.9 and 5.6 at theta=0 for the Turkish and the Norwegian families, respectively, indicating linkage between the disease and the D5S1995-D5S436 haplotype spanning a 9.3 cM interval. Patients of the two families presented with the strict clinical features of MSS. On the other hand, the study of two smaller French and Italian families, initially diagnosed as presenting an atypical MS syndrome, clearly excluded linkage from both the MSS locus on 5q31 and the CCFDN locus in 18qter. Patients of the two excluded families had all MSS features (but the myopathic changes) plus peripheral neuropathy and optic atrophy, and various combinations of microcornea, hearing impairment, seizures, Type I diabetes, cerebral atrophy and leucoencephalopathy, indicating that only the pure MSS syndrome is a homogeneous genetic entity.
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Affiliation(s)
- C Lagier-Tourenne
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/Université Louis-Pasteur, Illkirch, France
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Farah S, Sabry MA, Khuraibet AJ, Anim JT, Quasrawi B, Al-Khatam S, Al-Busairi W, Hussein JM, Khan RA, Al-Awadi SA. Marinesco-Sjögren syndrome in a Bedouin family. Acta Neurol Scand 1997; 96:387-91. [PMID: 9449477 DOI: 10.1111/j.1600-0404.1997.tb00303.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Marinesco-Sjögren syndrome is rarely reported in the Middle East. This is the 2nd report of Marinesco-Sjögren syndrome in an Arab family. The clinical features of 2 affected brothers are described. Electrophysiological studies of the 2 patients showed primarily myopathic changes, whereas sural nerve biopsy revealed segmental demyelination and axonal degeneration. The role of tissue biopsy and the relationship to different electrophysiological studies are discussed. Both patients were noticed to have abnormally short lateral 3 metatarsals, a feature not present in other healthy members of the family. We suggest that this feature should be considered part of the syndrome profile.
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Affiliation(s)
- S Farah
- Department of Neurology, Ibn Sina Hospital, Hawalli, Kuwait
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McLaughlin JF, Pagon RA, Weinberger E, Haas JE. Marinesco-Sjögren syndrome: clinical and magnetic resonance imaging features in three children. Dev Med Child Neurol 1996; 38:636-44. [PMID: 8674914 DOI: 10.1111/j.1469-8749.1996.tb12128.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The authors describe clinical and MRI features of a girl and two boys, aged 9, 17 and 19 years, respectively, with Marinesco-Sjögren syndrome. The clinical findings included the major features of the syndrome, including growth deficiency, ataxia, cataracts, hypogonadism (in two) and seizures (in two). Truncal hypotonia (in three), microcephaly (in two) and leg spasticity (in two) were also present. MRI showed a very small cerebellar vermis in all three patients, various supratentorial abnormalities, an apparently small anterior pituitary gland in two and the absence of a posterior pituitary gland in all three. The MRI features are similar to the few reported pathologic findings for persons with Marinesco-Sjögren syndrome. MRI may be helpful in the early diagnosis of the disorder.
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Affiliation(s)
- J F McLaughlin
- Division of Congenital Defects, Children's Hospital and Medical Center, Seattle, WA 98105-03714, USA
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McLaughlin JF, Pagon RA, Weinberger E, Haas JE. Marinesco-Sjögren syndrome: clinical and magnetic resonance imaging features in three children. Dev Med Child Neurol 1996; 38:363-70. [PMID: 8641542 DOI: 10.1111/j.1469-8749.1996.tb12103.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The authors describe clinical and MRI features of a girl and two boys, aged 9, 17 and 19 years, respectively, with Marinesco-Sjögren syndrome. The clinical findings included the major features of the syndrome, including growth deficiency, ataxia, cataracts, hypogonadism (in two) and seizures (in two). Truncal hypotonia (in three), microcephaly (in two) and leg spasticity (in two) were also present. MRI showed a very small cerebellar vermis in all three patients, various supratentorial abnormalities, an apparently small anterior pituitary gland in two and the absence of a posterior pituitary gland in all three. The MRI features are similar to the few reported pathologic findings for persons with Marinesco-Sjögren syndrome. MRI may be helpful in the early diagnosis of the disorder.
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Affiliation(s)
- J F McLaughlin
- Department of Pediatrics, Children's Hospital and Medical Center, Seattle, WA 98105-03714, USA
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Williams TE, Buchhalter JR, Sussman MD. Cerebellar dysplasia and unilateral cataract in Marinesco-Sjögren syndrome. Pediatr Neurol 1996; 14:158-61. [PMID: 8703231 DOI: 10.1016/0887-8994(96)83273-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The classic features of Marinesco-Sjögren syndrome include bilateral cataracts, cerebellar ataxia, and mental deficiency with an autosomal recessive inheritance pattern. Weakness and a variety of other characteristics are present inconsistently. A limited number of neuroimaging studies have indicated that cerebellar hypoplasia is the most common finding. We report a patient with near normal intelligence, unilateral cataract, and the previously unreported magnetic resonance imaging findings of cerebellar dysplasia, arachnoid cyst, and absent septum pellucidum. A review of the literature suggests significant heterogeneity in the Marinesco-Sjögren syndrome.
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Affiliation(s)
- T E Williams
- School of Medicine, Oregon Health Sciences University, Portland, USA
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Sasaki K, Suga K, Tsugawa S, Sakuma K, Tachi N, Chiba S, Imamura S. Muscle pathology in Marinesco-Sjogren syndrome: a unique ultrastructural feature. Brain Dev 1996; 18:64-7. [PMID: 8907346 DOI: 10.1016/0387-7604(95)00088-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The light- and electron-microscopical findings in the skeletal muscle of a patient with Marinesco-Sjogren syndrome (MSS) are presented. Muscle biopsy specimens showed myopathy with slightly dystrophic changes including variation in fiber size, muscle fiber necrosis, regeneration and rimmed vacuole formation. Fiber type analysis with myosin ATPase staining showed a mild increase in type 2C fibers. Electron microscopy revealed autophagic vacuoles with numerous myeloid bodies, and a unique dense membranous structure associated with nuclei. We consider that this unique membranous structure is an important feature in the muscle pathology of MSS.
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Affiliation(s)
- K Sasaki
- Department of Pediatrics, Hokkaido Prefectural Sapporo Rehabilitation Center for Disabled Children, Teine-ku, Japan
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Dimitrov GV, Lateva ZC, Dimitrova NA. Model of the slow components of skeletal muscle potentials. Med Biol Eng Comput 1994; 32:432-6. [PMID: 7967810 DOI: 10.1007/bf02524697] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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