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Studying the Stoichiometry of Epidermal Growth Factor Receptor in Intact Cells using Correlative Microscopy
09:16

Studying the Stoichiometry of Epidermal Growth Factor Receptor in Intact Cells using Correlative Microscopy

Published on: September 11, 2015

CIN85 associates with multiple effectors controlling intracellular trafficking of epidermal growth factor receptors

Katarzyna Kowanetz1, Koraljka Husnjak, Daniela Höller

  • 1Institute of Biochemistry II, Goethe University Medical School, 60590 Frankfurt, Germany.

Molecular Biology of the Cell
|April 20, 2004
PubMed

Insights

CIN85 acts as a scaffold protein, binding multiple endocytic proteins through a PxxxPR motif. This interaction is crucial for regulating epidermal growth factor (EGF) receptor trafficking and recycling.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Protein Interactions

Background:

  • CIN85 (Cbl-interacting protein of 85 kDa) is an adaptor protein.
  • It plays a role in Cbl-mediated down-regulation of epidermal growth factor (EGF) receptors.
  • CIN85's src homology 3 domains bind to a proline-arginine (PxxxPR) motif in Cbl, essential for EGF receptor endocytosis.

Purpose of the Study:

  • Identify novel CIN85 effectors containing the PxxxPR motif.
  • Investigate the role of CIN85 as a molecular scaffold in protein complex formation.
  • Elucidate CIN85's function in regulating EGF receptor trafficking.

Main Methods:

  • Identification of CIN85-interacting proteins with PxxxPR motifs.
  • Analysis of CIN85's scaffolding function in forming high-molecular-weight complexes.
  • Investigating the impact of ASAP1 (Arf GTPase-activating protein specific 1) overexpression and PxxxPR motif mutation on EGF receptor recycling.

Main Results:

  • Novel CIN85 effectors identified, including phosphatases (SHIP-1, synaptojanin 2B1), Arf GTPase-activating proteins (ASAP1, ARAP3), adaptor proteins (Hip1R, STAP1), and a Rho exchange factor (p115Rho GEF).
  • CIN85 acts as a scaffold, clustering these effectors into high-molecular-weight complexes.
  • ASAP1 overexpression enhanced EGF receptor recycling, while a mutated PxxxPR motif in ASAP1 abolished this effect, indicating its importance.

Conclusions:

  • CIN85 functions as a molecular scaffold, binding multiple endocytic accessory proteins via the PxxxPR motif.
  • This scaffolding activity is critical for controlling distinct steps in EGF receptor trafficking along endocytic and recycling pathways.

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