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Crystal structure of human POP1 and its distinct structural feature for PYD domain

Jae Young Choi1, Chang Min Kim1, Eun Kyung Seo1

  • 1School of Biotechnology and Graduate School of Biochemistry at Yeungnam University, Gyeongsan 712-749, South Korea.

Biochemical and Biophysical Research Communications
|April 4, 2015
PubMed

Insights

PYD only protein 1 (POP1) inhibits inflammasome formation by blocking ASC recruitment. This study reveals the crystal structure of POP1, offering insights into its anti-inflammatory mechanism.

Area of Science:

  • Immunology
  • Structural Biology
  • Biochemistry

Background:

  • Inflammatory caspases, like caspase-1, are crucial for innate immunity and activate via inflammasome complexes.
  • The inflammasome comprises Nod-like receptors, ASC (apoptosis-associated speck-like protein containing a CARD), and caspase-1.
  • ASC acts as an adaptor, bridging Nod-like receptors and caspase-1 through PYD-PYD and CARD-CARD interactions, respectively.

Purpose of the Study:

  • To elucidate the inhibitory mechanism of PYD only protein 1 (POP1) in inflammasome formation.
  • To determine the crystal structure of human POP1.
  • To provide structural basis for POP1's negative regulation of inflammatory responses.

Main Methods:

  • X-ray crystallography was used to determine the three-dimensional structure of human POP1.
  • Bioinformatic analysis and structural comparisons were employed to understand POP1's interaction with ASC.
  • The study speculates on the inhibitory mechanism based on the obtained crystal structure.

Main Results:

  • The crystal structure of human POP1 was successfully determined.
  • POP1 directly binds to ASC via PYD:PYD interactions, preventing ASC's recruitment to Nod-like receptors.
  • This interaction effectively blocks inflammasome assembly and subsequent caspase-1 activation.

Conclusions:

  • POP1 is a key negative regulator of the inflammasome pathway.
  • The crystal structure provides a molecular basis for POP1's inhibitory function.
  • Understanding POP1's mechanism can inform therapeutic strategies targeting inflammatory diseases.
Keywords:
Crystal structureInflammasomeInflammationInnate immunityPOP1PYD domain

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