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HAI-2 stabilizes, inhibits and regulates SEA-cleavage-dependent secretory transport of matriptase

Annika W Nonboe1, Oliver Krigslund1, Christoffer Soendergaard1,2

  • 1Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen North, Denmark.

Traffic (Copenhagen, Denmark)
|April 4, 2017
PubMed

Insights

Hepatocyte growth factor activator inhibitor-2 (HAI-2) mutations delay matriptase cleavage, affecting its transport and activity. This research clarifies HAI-2's role in regulating matriptase, crucial for cancer suppression.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Cancer Research

Background:

  • Hepatocyte growth factor activator inhibitor-2 (HAI-2) suppresses matriptase-induced carcinogenesis and promotes tumor regression.
  • The precise mechanisms underlying HAI-2's function remain incompletely understood.

Purpose of the Study:

  • To investigate the impact of specific HAI-2 Kunitz domain 1 mutations on matriptase processing and function.
  • To elucidate HAI-2's role in regulating matriptase maturation, transport, and proteolytic activity.

Main Methods:

  • Introduction of three mutations (K42N, C47F, R48L) into the HAI-2 Kunitz domain 1.
  • Analysis of matriptase SEA domain cleavage, endoplasmic reticulum (ER) accumulation, and proteolytic silencing.
  • Assessment of matriptase oligomerization, maturation, and folding.

Main Results:

  • Mutant HAI-2 proteins delayed SEA domain cleavage of matriptase, causing its accumulation in the ER.
  • Mutations affected matriptase oligomerization, maturation, and/or folding, influencing its transport to the plasma membrane.
  • Specific HAI-2 mutants exhibited reduced ability to proteolytically inhibit matriptase.

Conclusions:

  • HAI-2 plays a multifaceted role: stabilizing matriptase, regulating its transport via maturation/oligomerization, and inhibiting its proteolytic activity.
  • These findings provide new insights into the regulatory mechanisms of matriptase by HAI-2 within the secretory pathway.
  • Understanding these interactions is critical for developing targeted cancer therapies.
Keywords:
HAI-1HAI-2SEA domain cleavagechromogenic activitymatriptasesecretory transport

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