Related Experiment Video
Updated: Aug 7, 2026
04:36
Assay for Adhesion and Agar Invasion in S. cerevisiae
Published on: November 8, 2006
Multiple roles for cAMP-dependent protein kinase during Dictyostelium development
A J Harwood1, N A Hopper, M N Simon
1Imperial Cancer Research Fund, Clare Hall Laboratories, South Mimms, Herts, United Kingdom.
Developmental Biology
|January 1, 1992
Summary
Dictyostelium cAMP-dependent protein kinase (PKA) mutants reveal its crucial role in multicellular development. PKA inactivation disrupts cAMP relay and late-stage gene expression, impacting cell aggregation and slug formation.
Area of Science:
- Cellular and Molecular Biology
- Developmental Biology
- Biochemistry
Background:
- The cAMP-dependent protein kinase (PKA) holoenzyme in Dictyostelium consists of regulatory (R) and catalytic (C) subunits.
- Both R and C subunits increase in concentration during cellular aggregation, suggesting a role in development.
Purpose of the Study:
- To elucidate the function of PKA during Dictyostelium development.
- To investigate the roles of R subunit binding and inhibition of the C subunit.
- To understand the PKA pathway's involvement in cAMP signaling and multicellular organization.
Main Methods:
- Construction and analysis of Dictyostelium R subunit mutants defective in cAMP binding or C subunit inhibition.
- Phenotypic analysis of PKA-deficient cells (PKA-) in isolation and in chimeras with wild-type cells.
- Assessment of cAMP relay, cell aggregation, slug migration, and gene expression in PKA- mutants.
Main Results:
- Overexpression of the unmutated R subunit blocks development by directly inactivating the C subunit, not by affecting cAMP levels.
- PKA- cells exhibit defects in cAMP relay, leading to aggregation failure.
- PKA- cells are impaired in multicellular stages, showing abnormal migration in slugs and failure to express postaggregative genes, even in chimeric development.
Conclusions:
- PKA is essential for cAMP relay and proper multicellular development in Dictyostelium.
- The R subunit's inhibitory function on the C subunit is critical for regulating PKA activity during development.
- PKA plays a vital role in both early aggregation and later multicellular morphogenesis and gene expression.
Related Concept Videos
01:45Positive Regulator Molecules
To consistently produce healthy cells, the cell cycle—the process that generates daughter cells—must be precisely regulated.
01:57Protein Complexes with Interchangeable Parts
Groups of proteins may form a complex where each protein in this complex has a different role in the overall execution of the complex’s function. Often some of the proteins in the complex can be replaced by a closely related variant to give a complex that contains many of the same components yet is functionally distinct.
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...
01:29Cytoskeletal Proteins in Bacteria
Bacterial cells were initially considered simple, randomly organized structures lacking a cytoskeleton. However, the discovery of cytoskeleton homologs in bacteria led to the change of this opinion. Bacterial cytoskeletal filaments regulate the cell shape, cell polarity, cell division, and partitioning of plasmids during cell division. It was later discovered that bacterial cytoskeletal proteins, mainly actin and tubulin homologs, are diverse compared to their eukaryotic counterparts. On the...
02:39Positive Regulator Molecules
Mitotic cell division results in daughter cells that exactly resemble the parent cell. However, errors in the DNA replication or distribution of genetic material may lead to genetic mutations that may be passed down to every new cell formed from the resulting abnormal cell. Propagation of such mutant cells is restricted through checkpoint mechanisms present at different stages of the cell cycle. These checkpoints involve regulator molecules that either promote or demote cell cycle events.
01:13Actin Polymerization and Cell Motility
Actin is a family of globular proteins that are highly abundant in eukaryotic cells. It makes up approximately 1-5% of total cell protein concentration. Actin monomers polymerize to form a complex network of polarized filaments, the actin cytoskeleton, that plays a crucial role in many cellular processes, including cell motility, division, endocytosis, and metastasis of cancer cells.
Actin cytoskeleton dynamics can produce pushing, pulling, and resistance forces that help the cell to migrate.
Actin cytoskeleton dynamics can produce pushing, pulling, and resistance forces that help the cell to migrate.
01:25cAMP-dependent Protein Kinase Pathways
Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...