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Human interleukin-4 receptor signaling requires sequences contained within two cytoplasmic regions

K Koettnitz1, F S Kalthoff

  • 1Sandoz Research Institute, Vienna, Austria.

European Journal of Immunology
|April 1, 1993
PubMed

Insights

Researchers mapped the human interleukin-4 receptor (hIL-4R) signaling pathway. Key cytoplasmic regions essential for IL-4-induced cell growth were identified, crucial for understanding hematopoietin receptor superfamily signaling.

Area of Science:

  • Immunology
  • Molecular Biology
  • Cell Signaling

Background:

  • The signaling pathway of the human interleukin-4 receptor (hIL-4R) remains largely uncharacterized.
  • Understanding hIL-4R signaling is critical for elucidating immune responses and developing targeted therapies.

Purpose of the Study:

  • To identify the specific cytoplasmic regions of the hIL-4R essential for mediating biological responses after IL-4 binding.
  • To map the functional domains within the hIL-4R intracytoplasmic region.

Main Methods:

  • Cloning and expression of wild-type hIL-4R and cytoplasmic deletion mutants in the BA/F3 pro-B cell line.
  • Assessing IL-4-induced proliferation in transfected BA/F3 cells.
  • Analyzing the impact of specific cytoplasmic deletions on receptor signaling function.

Main Results:

  • Wild-type hIL-4R transfection enabled dose-dependent BA/F3 cell proliferation in response to human IL-4.
  • Two discontinuous cytoplasmic regions (amino acids IIe233-Ser365 and Thr462-Ala580) were identified as critical for hIL-4R signaling.
  • Deletion of either of these regions completely abolished IL-4-inducible cell growth.

Conclusions:

  • The signaling capability of hIL-4R is dependent on two distinct intracytoplasmic regions.
  • These findings provide crucial insights into the molecular mechanisms of hIL-4R function.
  • The results contribute to the broader understanding of signaling pathways within the hematopoietin receptor superfamily.

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