The par-3 gene is required for establishing polarity in early C. elegans embryos. Embryos from par-3 homozygous mothers show defects in segregation of cytoplasmic determinants and in positioning of the early cleavage spindles. We report here that the PAR-3 protein is asymmetrically distributed at the periphery of the zygote and asymmetrically dividing blastomeres of the germline lineage. The PAR-3 distribution is roughly the reciprocal of PAR-1, another protein required for establishing embryonic polarity in C. elegans. Analysis of the distribution of PAR-3 and PAR-1 in other par mutants reveals that par-2 activity is required for proper localization of PAR-3 and that PAR-3 is required for proper localization of PAR-1. In addition, the distribution of the PAR-3 protein correlates with differences in cleavage spindle orientation and suggests a mechanism by which PAR-3 contributes to control of cleavage pattern.
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http://dx.doi.org/10.1016/0092-8674(95)90187-6 | DOI Listing |
J Biol Chem
December 2024
Department of Chemistry and Biochemistry, Institute of Molecular Biology, 1229 University of Oregon, Eugene, Oregon, USA. Electronic address:
The Par complex polarizes the plasma membrane of diverse animal cells using the catalytic activity of atypical PKC (aPKC) to pattern substrates. Two upstream regulators of the Par complex, Cdc42 and Par-3, bind separately to the complex to influence its activity in different ways. Each regulator binds a distinct member of the complex, Cdc42 to Par-6 and Par-3 to aPKC, making it unclear how they influence one another's binding.
View Article and Find Full Text PDFbioRxiv
October 2024
Institute of Molecular Biology, Department of Chemistry and Biochemistry, 1229 University of Oregon, Eugene, OR 97403.
The Par complex polarizes the plasma membrane of diverse animal cells using the catalytic activity of atypical Protein Kinase C (aPKC) to pattern substrates. Two upstream regulators of the Par complex, Cdc42 and Par-3, bind separately to the complex to influence its activity in different ways. Each regulator binds a distinct member of the complex, Cdc42 to Par-6 and Par-3 to aPKC, making it unclear how they influence one another's binding.
View Article and Find Full Text PDFPLoS Genet
October 2024
Department of Biological Sciences, Graduate School of Science, The University of Osaka, Toyonaka, Osaka, Japan.
Complex organ structures are formed with high reproducibility. To achieve such intricate morphologies, the responsible epithelium undergoes multiple simultaneous shape changes, such as elongation and folding. However, these changes have typically been assessed separately.
View Article and Find Full Text PDFbioRxiv
August 2024
Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637.
Studies of PAR polarity have emphasized a paradigm in which mutually antagonistic PAR proteins form complementary polar domains in response to transient cues. A growing body of work suggests that the oligomeric scaffold PAR-3 can form unipolar asymmetries without mutual antagonism, but how it does so is largely unknown. Here we combine single molecule analysis and modeling to show how the interplay of two positive feedback loops promote dynamically stable unipolar PAR-3 asymmetries in early embryos.
View Article and Find Full Text PDFDokl Biochem Biophys
October 2024
Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
Aim: Molecular alterations of diabetic gastroenteropathy are poorly identified. This study investigates the effects of prolonged GABA supplementation on key protein expression levels of trypsin-1, PAR-1, PAR-2, PAR-3, PI3K, Akt, COX-2, GABAA, and GABAB receptors in the gastric tissue of type 2 diabetic rats (T2DM).
Method: To induce T2DM, a 3-month high-fat diet and 35 mg/kg of streptozotocin was used.
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