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Structural insights into the inhibited states of the Mer receptor tyrosine kinase

Xudong Huang1, Patrick Finerty, John R Walker

  • 1Structural Genomics Consortium, University of Toronto, Ont., Canada.

Journal of Structural Biology
|November 26, 2008
PubMed

Insights

Mer (MerTK) is a receptor tyrosine kinase crucial for phagocytosis and cell clearance. Structural analysis reveals its autoinhibited state and how a ligand alters its conformation, offering insights into its function and potential therapeutic development.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Background:

  • Mer (MerTK) is a receptor tyrosine kinase involved in phagocytosis, cell clearance, and platelet aggregation.
  • Mer knockout mice show protection against thrombosis, while Mer overexpression is linked to carcinomas.
  • The precise mechanism by which Mer initiates phagocytosis remains unclear.

Purpose of the Study:

  • To elucidate the structural mechanisms underlying Mer (MerTK) autoinhibition and ligand-induced conformational changes.
  • To provide a structural basis for understanding MerTK-related diseases and developing targeted chemical probes.

Main Methods:

  • High-resolution structural analysis of Mer (MerTK) in its autoinhibited state.
  • Structural determination of Mer (MerTK) complexed with the ligand compound-52 (C52).
  • Comparative analysis of conformational states to understand functional mechanisms.

Main Results:

  • Mer (MerTK) adopts an autoinhibited alphaC-Glu-out conformation with an activation loop residue in the active site.
  • Complexation with C52 maintains the DFG-Asp-in and alphaC-Glu-out states but induces other conformational changes.
  • C52 binding alters the proximity of the alphaC helix and DFGL region to the hinge, compressing the active site pocket.

Conclusions:

  • The identified conformational states reveal MerTK's autoinhibition mechanisms.
  • Provides insights into the pathophysiological basis of disease-associated mutations.
  • Establishes a structural platform for developing chemical probes targeting MerTK.

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