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Distinct domains of CD98hc regulate integrins and amino acid transport

C A Fenczik1, R Zent, M Dellos

  • 1Department of Vascular Biology, The Scripps Research Institute, La Jolla, California 92037 , USA.

The Journal of Biological Chemistry
|December 31, 2000
PubMed

Insights

The cell surface protein CD98 (CD98hc) has two distinct functions: amino acid transport and integrin regulation. These functions are separable and rely on different protein domains, offering new insights into cell signaling.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • CD98 is a heterodimeric cell surface protein composed of CD98 heavy chain (CD98hc) linked to various light chains.
  • CD98hc functions as an amino acid transporter and also interacts with integrin beta(1A) to regulate integrin function.

Purpose of the Study:

  • To investigate the relationship between CD98hc's roles in amino acid transport and integrin function.
  • To determine which domains of CD98hc are responsible for each specific function.

Main Methods:

  • Construction of chimeric proteins combining CD98hc with CD69, a type II transmembrane protein.
  • Analysis of amino acid transport (isoleucine) and integrin binding/function in cells expressing wild-type and mutant CD98hc.

Main Results:

  • The cytoplasmic and transmembrane domains of CD98hc are essential for its effects on integrin function.
  • The extracellular domain of CD98hc is required for stimulating isoleucine transport.
  • A CD98hc mutant lacking the integrin binding site could still enhance isoleucine transport.

Conclusions:

  • The amino acid transport and integrin regulation functions of CD98hc are distinct and separable.
  • Different domains of CD98hc mediate these two critical cellular processes.

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