The molecular chaperone Hsp90α deficiency causes retinal degeneration by disrupting Golgi organization and vesicle transportation in photoreceptors

J Mol Cell Biol. 2020 Apr 24;12(3):216-229. doi: 10.1093/jmcb/mjz048.


Heat shock protein 90 (Hsp90) is an abundant molecular chaperone with two isoforms, Hsp90α and Hsp90β. Hsp90β deficiency causes embryonic lethality, whereas Hsp90α deficiency causes few abnormities except male sterility. In this paper, we reported that Hsp90α was exclusively expressed in the retina, testis, and brain. Its deficiency caused retinitis pigmentosa (RP), a disease leading to blindness. In Hsp90α-deficient mice, the retina was deteriorated and the outer segment of photoreceptor was deformed. Immunofluorescence staining and electron microscopic analysis revealed disintegrated Golgi and aberrant intersegmental vesicle transportation in Hsp90α-deficient photoreceptors. Proteomic analysis identified microtubule-associated protein 1B (MAP1B) as an Hsp90α-associated protein in photoreceptors. Hspα deficiency increased degradation of MAP1B by inducing its ubiquitination, causing α-tubulin deacetylation and microtubule destabilization. Furthermore, the treatment of wild-type mice with 17-DMAG, an Hsp90 inhibitor of geldanamycin derivative, induced the same retinal degeneration as Hsp90α deficiency. Taken together, the microtubule destabilization could be the underlying reason for Hsp90α deficiency-induced RP.

Keywords: Golgi disintegration; Hsp90α; MAP1B; acetylated α-tubulin; cytoskeleton; microtubule; retinitis pigmentosa; vesicle transportation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / genetics
  • Biological Transport
  • Disease Models, Animal
  • Disease Susceptibility
  • Gene Expression
  • Genotype
  • Golgi Apparatus / metabolism*
  • Golgi Apparatus / ultrastructure
  • HSP90 Heat-Shock Proteins / antagonists & inhibitors
  • HSP90 Heat-Shock Proteins / deficiency*
  • Mice
  • Mice, Knockout
  • Microtubules / metabolism
  • Photoreceptor Cells / metabolism*
  • Photoreceptor Cells / ultrastructure
  • Retinal Degeneration / etiology*
  • Retinal Degeneration / metabolism*
  • Retinal Degeneration / pathology
  • Transport Vesicles / metabolism*


  • HSP90 Heat-Shock Proteins