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Updated: Jun 13, 2026
07:51
Pull-down of Calmodulin-binding Proteins
Published on: January 23, 2012
FADD-calmodulin interaction: a novel player in cell cycle regulation
Giuliana Papoff1, Nadia Trivieri, Roberta Crielesi
1Istituto di Biologia Cellulare, Consiglio Nazionale delle Ricerche, Campus A. Buzzati-Traverso, Monterotondo, Rome, Italy.
Biochimica Et Biophysica Acta
|April 28, 2010
Summary
FAS-associated death domain (FADD) interacts with calmodulin (CaM), a calcium-binding protein, influencing cell cycle progression and survival. This interaction, regulated by casein kinase I alpha (CKIalpha), plays a role in cell fate determination.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- FAS-associated death domain (FADD) is crucial for regulating cell fate, apoptosis, cell cycle, and proliferation.
- Calmodulin (CaM), a calcium-binding protein, mediates calcium signals and regulates cell cycle progression and survival.
Purpose of the Study:
- To identify novel regulatory mechanisms of FADD function.
- To characterize the interaction between FADD and CaM and its functional consequences.
Main Methods:
- Screening of a lambda-phage cDNA library to identify FADD-interacting proteins.
- Characterization of CaM binding sites in FADD using biochemical and cell-based assays.
- Analysis of FADD phosphorylation by casein kinase I alpha (CKIalpha).
- Co-localization studies of FADD, CaM, and CKIalpha in HeLa cells.
- Complementation experiments in Jurkat FADD-/- T cells using FADD mutants.
Main Results:
- Calmodulin (CaM) was identified as a novel FADD-interacting protein.
- Two calcium-dependent CaM binding sites were characterized in FADD (alpha helices 8-9 and 10-11).
- Both FADD and CaM are substrates for CKIalpha, and they co-localize with CKIalpha at the mitotic spindle.
- Mutations in CaM binding sites of FADD protect cells from Taxol-induced cell cycle arrest.
- FADD/CaM interaction is not essential for Fas-mediated apoptosis, but CaM may compete with Fas for FADD binding.
Conclusions:
- The interplay between FADD, CaM, and CKIalpha is critical for regulating cell fate.
- CaM binding to FADD influences cell cycle progression, independent of apoptosis.
- CKIalpha-mediated phosphorylation of FADD and CaM contributes to their functional interaction during mitosis.
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