Faculty and Research

Biography

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The main research focus in the Chai laboratory is a novel “extracellular membrane-associated serine protease proteolytic activation and action network”, involving the glycosylphosphatidylinositol (GPI)-anchored prostasin (PRSS8), the type-II transmembrane hepsin (TMPRSS1) and matriptase (PRSS14), and the urokinase-type plasminogen activator (uPA) with its GPI-anchored plasma membrane receptor uPAR. This novel serine protease activation and action network has direct impacts on the cellular signals mediated by two major classes of membrane receptors, the receptor tyrosine kinases (RTKs) represented by the epidermal growth factor receptor (EGFR/ErbB1/Her-1) and the G-protein-coupled receptors (GPCRs) such as the protease-activated receptor 2 (PAR-2). Ultimately, this extracellular membrane-associated serine protease activation and action network is essential for maintaining epithelial homeostasis but is also implicated in the pathophysiology of many epithelial cancers. 

Recent Publications

  1. Chen L-M, Chai KX. Autologous Paracrine Prostasin–Matriptase Serine Protease Interaction in Lymphoid Cancer Cells. Cells. 2025; 14(4):247. PMID: 39996720 
  2. Chen LM, Chai KX. Exosome-Mediated Activation of the Prostasin-Matriptase Serine Protease Cascade in B Lymphoma Cells. Cancers (Basel). 2023 Jul 28;15(15):3848. PMID: 37568664 
  3. Reddy NR, Dicce A, Ma Y, Chen LM, Chai KX, Fang J. Crystalline H-aggregate nanoparticles for detecting dopamine release from M17 human neuroblastoma cells. J Mater Chem B. 2022 Oct 12;10(39):8024-8032. PMID: 36098268
  4. Chen LM, Chai JC, Liu B, Strutt TM, McKinstry KK, Chai KX. Prostasin regulates PD-L1 expression in human lung cancer cells. Biosci Rep. 2021 Jul 30;41(7):BSR20211370. PMID: 34240739
  5. Chen LM, Chai KX. Matriptase cleaves the amyloid-beta peptide 1-42 at Arg-5, Lys-16, and Lys-28. BMC Res Notes. 2019 Jan 3;12(1):5. PMID: 30606244

Books

  1. Making “Sense” of Genetics Today, Author: KARL CHAI, Edition: 1, Copyright: 2025, Pages: 206. Kendall Hunt Publishing Company ISBN 9798385111411
  2. Interpretive Molecular Biology, Author: KARL CHAI, Edition: First, Copyright: 2020, Pages: 223. Kendall Hunt Publishing Company ISBN 9781792478970

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