title: Induction and phosphorylation of the small heat shock   proteins HspB1/Hsp25 and HspB5/αB-crystallin in the rat retina   upon optic nerve injury.
abstract: Several eye diseases are associated with axonal injury in the optic nerve, which normally leads to degeneration of retinal ganglion cells (RGCs) and subsequently to loss of vision. There is experimental evidence that some members of the small heat shock protein family (HspBs) are upregulated upon optic nerve injury (ONI) in the retina and sufficient to promote RGC survival. These data raise the question as to whether other family members may play a similar role in this context. Here, we performed a comprehensive comparative study comprising all HspBs in an experimental model of ONI. We found that five HspBs were expressed in the adult rat retina at control conditions but only HspB1 and HspB5 were upregulated in response to ONI. Furthermore, HspB1 and HspB5 were constitutively phosphorylated in Müller cells at serine 15 and serine 59, respectively. In RGCs, phosphorylation was stimulated by ONI and occurred at serine 86 of HspB1 and at serine 19 and 45 of HspB5. These data suggest that of all small heat shock proteins, only HspB1 and HspB5 might be of protective value for RGCs after ONI and that this process might be regulated by phosphorylation at serine 86 of HspB1 and serine 19 and serine 45 of HspB5. The molecular targets of phosphoHspB1 and phosphoHspB5 remain to be identified.
authors.affiliation: Institute of Anatomy and Cell Biology, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmidt
authors.affiliation: Department of Experimental Neurology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Fischer
authors.affiliation: Department of Experimental Neurology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Andreadaki
authors.affiliation: Institute of Anatomy and Cell Biology, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany.
authors.forename: Britta
authors.initials: B
authors.lastname: Bartelt-Kirbach
authors.affiliation: Institute of Anatomy and Cell Biology, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany. nikola.golenhofen@uni-ulm.de.
authors.forename: Nikola
authors.initials: N
authors.lastname: Golenhofen
mesh_terms: D000818:Animals; D003459:Crystallins / Q000378:metabolism*; D005260:Female; D055551:HSP27 Heat-Shock Proteins / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D000066829:Neuroprotection / Q000502:physiology*; D020221:Optic Nerve Injuries / Q000473:pathology*; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012165:Retinal Ganglion Cells / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D003459:Crystallins; D055551:HSP27 Heat-Shock Proteins; C486114:Hspb1 protein, rat; D008869:Microtubule-Associated Proteins; C530883:cryaB protein, rat