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Author Spotlight: Identifying Compensatory Pathways in Malaria Parasites Containing Hypomorphic Allele of Essential Protein Kinases
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Author Spotlight: Identifying Compensatory Pathways in Malaria Parasites Containing Hypomorphic Allele of Essential Protein Kinases

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HPK1 citron homology domain regulates phosphorylation of SLP76 and modulates kinase domain interaction dynamics

Avantika S Chitre1, Ping Wu1, Benjamin T Walters1

  • 1Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA.

Nature Communications
|May 2, 2024
PubMed

Insights

Hematopoietic progenitor kinase 1's citron homology domain (CHD) regulates T-cell signaling by binding the kinase domain (KD). This interaction is crucial for HPK1's function in cancer immunotherapy.

Area of Science:

  • Biochemistry
  • Structural Biology
  • Immunology

Background:

  • Hematopoietic progenitor kinase 1 (HPK1) negatively regulates T-cell receptor signaling.
  • HPK1 is a potential target for cancer immunotherapy.
  • The function of HPK1's citron homology domain (CHD) is largely unknown, unlike its kinase domain (KD).

Purpose of the Study:

  • To elucidate the structure-function relationship of the HPK1 CHD in relation to its KD.
  • To understand how the CHD contributes to HPK1's regulatory role in T-cell signaling.

Main Methods:

  • X-ray crystallography
  • Hydrogen-deuterium exchange mass spectrometry (HDX-MS)
  • Site-directed mutagenesis
  • Biochemical assays

Main Results:

  • The HPK1 CHD possesses a seven-bladed β-propeller fold and binds to the HPK1 KD.
  • Interaction between CHD and KD directly correlates with negative regulation of kinase activity.
  • CHD enhances HPK1 protein stability and facilitates substrate SLP76 docking.

Conclusions:

  • The HPK1 CHD plays a critical role in both direct and indirect regulation of HPK1 activity.
  • Understanding the CHD-KD interaction provides insights into HPK1 function and potential therapeutic strategies for cancer immunotherapy.

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