Localization of the zinc binding tubulin polymerization promoting protein in the mice and human eye

Robert G. Tripon, Judit Oláh, Tajwar Nasir, Lajos Csincsik, Chee Lok Li, Sándor Szunyogh, Haiyan Gong, Jane M. Flinn, Judit Ovádi, Imre Lengyel

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Tubulin Polymerization Promoting Protein (TPPP/p25) modulates the dynamics and stability of the microtubule network by its bundling and acetylation enhancing activities that can be modulated by the binding of zinc to TPPP/p25. Its expression is essential for the differentiation of oligodendrocytes, the major constituents of the myelin sheath, and has been associated with neuronal inclusions. In this paper, evidence is provided for the expression and localization of TPPP/p25 in the zinc-rich retina and in the oligodendrocytes in the optic nerve. Localization of TPPP/p25 was established by confocal microscopy using calbindin and synaptophysin as markers of specific striations in the inner plexiform layer (IPL) and presynaptic terminals, respectively. Postsynaptic nerve terminals in striations S1, S3 and S5 in the IPL and a subset of amacrine cells show immunopositivity against TPPP/p25 both in mice and human eyes. The co-localization of TPPP/p25 with acetylated tubulin was detected in amacrine cells, oligodendrocyte cell bodies and in synapses in the IPL. Quantitative Western blot revealed that the TPPP/p25 level in the retina was 0.05–0.13 ng/μg protein, comparable to that in the brain. There was a central (from optic nerve head) to peripheral retinal gradient in TPPP/p25 protein levels. Our in vivo studies revealed that the oral zinc supplementation of mice significantly increased TPPP/p25 as well as acetylated tubulin levels in the IPL. These results suggest that TPPP/p25, a microtubule stabilizer can play a role in the organization and reorganization of synaptic connections and visual integration in the eye.

Original languageEnglish
Pages (from-to)222-230
Number of pages9
JournalJournal of Trace Elements in Medicine and Biology
Volume49
DOIs
Publication statusPublished - Sep 2018

Keywords

  • Amacrine cell
  • Inner plexiform layer
  • Myelin sheath
  • Retina
  • Tubulin polymerization promoting protein
  • Zinc

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Medicine
  • Inorganic Chemistry

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