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Molecular basis underlying functional pleiotropy of cytokines and growth factors
1Division of Molecular Oncology, Department of Oncology, Biomedical Research Center, Osaka University Graduate School of Medicine (C7), 2-2, Yamada-oka, Suita, Osaka, 565-0871, Japan. hirano@molonc.med.osaka-u.ac.jp
Abstract:
Cytokines and growth factors play pivotal roles in cell growth, differentiation, and cell survival. Ligand binding to the receptors induces dimerization or oligomerization of the receptors, resulting in the activation of a variety of signal transduction pathways. The interplay among these multiple signals is critically involved in the biological activities of cytokines and growth factors. In this minireview, I discuss two models. One is the "receptor conversion model": The complex of cytokine and its soluble form of receptor acts like a cytokine with novel target specificity. The other is the "orchestrating model": Cytokines can simultaneously generate contradictory signals in the same target cells and the balance of each contradictory signal may determine the final output of cytokine signals to express unified biological activity. These mechanisms are part of the molecular basis underlying functional pleiotropy of cytokines and growth factors.
Insights
Cytokines and growth factors utilize two models—receptor conversion and signal orchestration—to regulate cell activities. These mechanisms explain how these signaling molecules achieve diverse biological effects.
Area of Science:
- Molecular Biology
- Cell Signaling
- Biochemistry
Background:
- Cytokines and growth factors are crucial for cell growth, differentiation, and survival.
- Receptor activation through ligand binding initiates diverse signal transduction pathways.
- The complex interplay of these signals dictates cellular responses.
Purpose of the Study:
- To review two proposed models explaining the functional pleiotropy of cytokines and growth factors.
- To elucidate the molecular mechanisms behind the diverse biological activities of these signaling molecules.
Main Methods:
- Review of existing literature on cytokine and growth factor signaling.
- Discussion of the 'receptor conversion model' and the 'orchestrating model'.
Main Results:
- The 'receptor conversion model' proposes that cytokine-soluble receptor complexes exhibit novel target specificities.
- The 'orchestrating model' suggests that cytokines generate balanced, contradictory signals within cells to achieve unified biological activity.
Conclusions:
- These models provide insights into the molecular basis of functional pleiotropy in cytokines and growth factors.
- Understanding these signaling mechanisms is key to comprehending complex cellular processes.