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The angiotensin II type 1 receptor C-terminal Lys residues interact with tubulin and modulate receptor export

Xiaoping Zhang1, Hong Wang, Matthew T Duvernay

  • 1Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America.

Plos One
|March 2, 2013
PubMed

Insights

Angiotensin II type 1 receptor (AT1R) transport relies on tubulin binding. Specific lysine residues in AT1R

Area of Science:

  • Molecular biology
  • Cellular transport mechanisms
  • Receptor trafficking

Background:

  • Angiotensin II type 1 receptor (AT1R) mediates angiotensin II's physiological and pathological roles.
  • The intracellular transport pathway of AT1R from the endoplasmic reticulum (ER) to the cell surface is not well understood.

Purpose of the Study:

  • To elucidate the molecular mechanisms governing the cell surface transport of newly synthesized AT1R.
  • To identify specific interactions involved in AT1R trafficking.

Main Methods:

  • Investigated the interaction between AT1R's C-terminus (CT) and tubulin using biochemical binding assays.
  • Mapped the binding domains on both AT1R and tubulin.
  • Utilized site-directed mutagenesis to disrupt AT1R-tubulin binding.
  • Assessed cell surface expression of AT1R and AT1R-mediated signaling (ERK1/2 activation) in wild-type and mutant receptors.

Main Results:

  • Demonstrated a direct and strong binding interaction between the AT1R C-terminus and tubulin.
  • Identified two specific lysine residues (Lys310 and Lys311) in the AT1R CT juxtamembrane region and the acidic CT of tubulin as key binding sites, suggesting ionic interactions.
  • Disruption of tubulin binding via mutation significantly inhibited AT1R cell surface expression and caused AT1R to accumulate in the ER.
  • Attenuated AT1R-mediated ERK1/2 activation signaling.

Conclusions:

  • Specific lysine residues in the AT1R C-terminus are critical for its interaction with tubulin.
  • This AT1R-tubulin interaction regulates AT1R processing and transport from the ER to the cell surface.
  • The microtubule network plays a significant role in AT1R cell surface delivery.

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