HOMEPRODUCTSCOMPANYCONTACTFAQResearchDictionaryPharmaSign Up FREE or Login

Axotrophin/MARCH7 acts as an E3 ubiquitin ligase and ubiquitinates tau protein in vitro impairing microtubule binding.

Abstract
Tau is the major microtubule-associated protein in neurons involved in microtubule stabilization in the axonal compartment. Changes in tau gene expression, alternative splicing and posttranslational modification regulate tau function and in tauopathies can result in tau mislocalization and dysfunction, causing tau aggregation and cell death. To uncover proteins involved in the development of tauopathies, a yeast two-hybrid system was used to screen for tau-interacting proteins. We show that axotrophin/MARCH7, a RING-variant domain containing protein with similarity to E3 ubiquitin ligases interacts with tau. We defined the tau binding domain to amino acids 552-682 of axotrophin comprising the RING-variant domain. Co-immunoprecipitation and co-localization confirmed the specificity of the interaction. Intracellular localization of axotrophin is determined by an N-terminal nuclear targeting signal and a C-terminal nuclear export signal. In AD brain nuclear localization is lost and axotrophin is rather associated with neurofibrillary tangles. We find here that tau becomes mono-ubiquitinated by recombinant tau-interacting RING-variant domain, which diminishes its microtubule-binding. In vitro ubiquitination of four-repeat tau results in incorporation of up to four ubiquitin molecules compared to two molecules in three-repeat tau. In summary, we present a novel tau modification occurring preferentially on 4-repeat tau protein which modifies microtubule-binding and may impact on the pathogenesis of tauopathies.
AuthorsKatharina Flach, Ellen Ramminger, Isabel Hilbrich, Annika Arsalan-Werner, Franziska Albrecht, Lydia Herrmann, Michel Goedert, Thomas Arendt, Max Holzer
JournalBiochimica et biophysica acta (Biochim Biophys Acta) Vol. 1842 Issue 9 Pg. 1527-38 (Sep 2014) ISSN: 0006-3002 [Print] Netherlands
PMID24905733 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
CopyrightCopyright © 2014 Elsevier B.V. All rights reserved.
Chemical References
  • Mapt protein, mouse
  • Recombinant Proteins
  • Ubiquitin
  • tau Proteins
  • MARCHF7 protein, human
  • Ubiquitin-Protein Ligases
Topics
  • Aged
  • Alzheimer Disease (metabolism, pathology)
  • Animals
  • Blotting, Western
  • Brain (metabolism)
  • Case-Control Studies
  • Cell Proliferation
  • Cells, Cultured
  • Humans
  • Immunoenzyme Techniques
  • Immunoprecipitation
  • Mice
  • Mice, Knockout
  • Microtubules (metabolism)
  • Protein Binding
  • Recombinant Proteins (metabolism)
  • Two-Hybrid System Techniques
  • Ubiquitin (metabolism)
  • Ubiquitin-Protein Ligases (metabolism)
  • Ubiquitination
  • tau Proteins (physiology)

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research graph!


Choose Username:
Email:
Password:
Verify Password:
Enter Code Shown: