Myosin VIIA is protein that in humans is encoded by the MYO7A gene.[5] Myosin VIIA is a member of the unconventional myosin superfamily of proteins.[6] Myosins are actin binding molecular motors that use the enzymatic conversion of ATP - ADP + inorganic phosphate (Pi) to provide the energy for movement.

MYO7A
Available structures
PDBOrtholog search: PDBe RCSB
Identifiers
AliasesMYO7A, DFNA11, DFNB2, MYOVIIA, MYU7A, NSRD2, USH1B, myosin VIIA
External IDsOMIM: 276903; MGI: 104510; HomoloGene: 219; GeneCards: MYO7A; OMA:MYO7A - orthologs
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_000260
NM_001127179
NM_001127180
NM_001369365

NM_001256081
NM_001256082
NM_001256083
NM_008663

RefSeq (protein)

NP_000251
NP_001120652
NP_001356294

NP_001243010
NP_001243011
NP_001243012
NP_032689

Location (UCSC)Chr 11: 77.13 – 77.22 MbChr 7: 97.7 – 97.77 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

Myosins are mechanochemical proteins characterized by the presence of a motor domain, an actin-binding domain, a neck domain that interacts with other proteins, and a tail domain that serves as an anchor. Myosin VIIA is an unconventional myosin with the longest tail (1360 aa). The tail is expected to dimerize, resulting in a two-headed molecule. Unconventional myosins have diverse functions in eukaryotic cells and are primarily thought to be involved in the movement or linkage of intra-cellular membranes and organelles to the actin cytoskeleton via interactions mediated by their highly divergent tail domains.

MYO7A is expressed in a number of mammalian tissues, including testis, kidney, lung, inner ear, retina and the ciliated epithelium of the nasal mucosa.

Clinical significance

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Mutations in the MYO7A gene cause the Usher syndrome type 1B, a combined deafness/blindness disorder.[6] Affected individuals are typically profoundly deaf at birth and then undergo progressive retinal degeneration.[7]

Model organisms

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Model organisms have been used in the study of MYO7A function. A spontaneous mutant mouse line, called Myo7ash1-6J[19] was generated. Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion.[17][20] Twenty three tests were carried out on mutant mice and ten significant abnormalities were observed.[17] Male homozygous mutant mice displayed a decreased body weight, a decrease in body fat, improved glucose tolerance and abnormal pelvic girdle bone morphology. Homozygous mutant mice of both sex displayed various abnormalities in a modified SHIRPA test, including abnormal gait, tail dragging and an absence of pinna reflex, a decrease in grip strength, an increased thermal pain threshold, severe hearing impairment and a number of abnormal indirect calorimetry and clinical chemistry parameters.[17]

References

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  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000137474Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000030761Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ Hasson T, Skowron JF, Gilbert DJ, Avraham KB, Perry WL, Bement WM, Anderson BL, Sherr EH, Chen ZY, Greene LA, Ward DC, Corey DP, Mooseker MS, Copeland NG, Jenkins NA (September 1996). "Mapping of unconventional myosins in mouse and human". Genomics. 36 (3): 431–9. doi:10.1006/geno.1996.0488. PMID 8884266.
  6. ^ a b Weil D, Blanchard S, Kaplan J, Guilford P, Gibson F, Walsh J, Mburu P, Varela A, Levilliers J, Weston MD (March 1995). "Defective myosin VIIA gene responsible for Usher syndrome type 1B". Nature. 374 (6517): 60–1. Bibcode:1995Natur.374...60W. doi:10.1038/374060a0. PMID 7870171. S2CID 4324416.
  7. ^ Smith RJ, Berlin CI, Hejtmancik JF, Keats BJ, Kimberling WJ, Lewis RA, Möller CG, Pelias MZ, Tranebjaerg L (March 1994). "Clinical diagnosis of the Usher syndromes. Usher Syndrome Consortium". American Journal of Medical Genetics. 50 (1): 32–8. doi:10.1002/ajmg.1320500107. PMID 8160750.
  8. ^ "Body weight data for Myo7a". Wellcome Trust Sanger Institute.
  9. ^ "Neurological assessment data for Myo7a". Wellcome Trust Sanger Institute.
  10. ^ "Grip strength data for Myo7a". Wellcome Trust Sanger Institute.
  11. ^ "Hot plate data for Myo7a". Wellcome Trust Sanger Institute.
  12. ^ "Indirect calorimetry data for Myo7a". Wellcome Trust Sanger Institute.
  13. ^ "Glucose tolerance test data for Myo7a". Wellcome Trust Sanger Institute.
  14. ^ "DEXA data for Myo7a". Wellcome Trust Sanger Institute.
  15. ^ "Radiography data for Myo7a". Wellcome Trust Sanger Institute.
  16. ^ "Clinical chemistry data for Myo7a". Wellcome Trust Sanger Institute.
  17. ^ a b c d Gerdin AK (2010). "The Sanger Mouse Genetics Programme: High throughput characterisation of knockout mice". Acta Ophthalmologica. 88: 925–7. doi:10.1111/j.1755-3768.2010.4142.x. S2CID 85911512.
  18. ^ Mouse Resources Portal, Wellcome Trust Sanger Institute.
  19. ^ "Mouse Genome Informatics".
  20. ^ van der Weyden L, White JK, Adams DJ, Logan DW (2011). "The mouse genetics toolkit: revealing function and mechanism". Genome Biology. 12 (6): 224. doi:10.1186/gb-2011-12-6-224. PMC 3218837. PMID 21722353.
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Further reading

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