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The PAR-aPKC system: lessons in polarity.
1Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fuku-ura, Kanazawa-ku, Yokohama 236-0004, Japan. abell@med.yokohama-cu.ac.jp
Journal of Cell Science
|March 10, 2006
Summary
The PAR-aPKC system, including PAR-1 and PAR-3 proteins, is crucial for cell polarity and asymmetric division. This conserved system establishes complementary membrane domains through antagonistic interactions, though mechanisms vary by cell type.
Area of Science:
- Cell Biology
- Developmental Biology
- Genetics
Background:
- PAR-1 (protein kinase) and PAR-3 (scaffold protein) are key PAR genes.
- These genes are essential for asymmetric cell division in Caenorhabditis elegans.
- They are part of the evolutionarily conserved PAR-aPKC system involved in cell polarity.
Purpose of the Study:
- To review the conserved PAR-aPKC system's role in establishing cell polarity.
- To highlight how this system converts initial polarity cues into membrane domains.
- To discuss the divergent mechanisms linking PAR-aPKC to cellular machinery across cell types.
Main Methods:
- Literature review of studies on PAR genes and cell polarity.
- Analysis of conserved molecular mechanisms in various biological contexts.
- Examination of antagonistic interactions within the PAR-aPKC system.
Main Results:
- The PAR-aPKC system acts as molecular machinery for establishing cell polarity.
- It converts polarity cues into complementary membrane domains.
- Antagonistic interactions between complexes (aPKC-PAR-3-PAR-6 and PAR-1/PAR-2) are a common principle.
- Mechanisms of linking PAR-aPKC to other cellular machinery are cell-type specific.
Conclusions:
- The PAR-aPKC system is fundamental for cell polarity across diverse organisms.
- Mutual antagonism between PAR protein complexes is a conserved mechanism.
- Cell-type specific variations exist in how PAR-aPKC integrates with cellular components to establish polarity.
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