par-1, a gene required for establishing polarity in C. elegans embryos, encodes a putative Ser/Thr kinase that is asymmetrically distributed

Abstract

The first cleavage of C. elegans is asymmetric, generating daughter cells with different sizes, cytoplasmic components, and fates. Mutations in the par-1 gene disrupt this asymmetry. We report here that par-1 encodes a putative Ser/Thr kinase with similarity to kinases from yeasts and mammals. Two strong alleles have mutations in the kinase domain, suggesting that kinase activity is essential for par-1 function. PAR-1 protein is localized to the posterior periphery of the zygote and is distributed in a polar fashion preceding the asymmetric divisions of the germline lineage. Because PAR-1 distribution in the germline correlates with the distribution of germline-specific P granules, it is possible that PAR-1 functions in germline development as well as in establishing embryonic polarity.

A role for LKB1 gene in human cancer beyond the Peutz–Jeghers syndrome

“…Some of these AMPK-related kinases are the MAP/microtubule affinity-regulating kinases (MARK1, MARK2, MARK3 and MARK4) involved in microtubule stabilization, which may be related with the proposed role of LKB1 in cell polarity. Supporting this, LKB1 is homologous to the Par-4 genes of Caenorhabditis elegans, essential for establishing anterior-posterior (A-P) axis during embryonic development (Guo and Kemphues, 1995), and to the Drosophila lkb1, also required for the early A-P polarity of the oocyte, and for the repolarization of the oocyte cytoskeleton that defines the embryonic A-P axis (Martin and St Johnston, 2003). In mammalians, LKB1 induces complete polarization of intestinal epithelial cells in a cellautonomous fashion (Baas et al, 2004).…”

Par6 regulates skeletogenesis and gut differentiation in sea urchin larvae

“…Partitioning-defective (par) genes, which were originally identified in Caenorhabditis elegans, regulate asymmetric division of the zygote (Kemphues et al 1988;Guo and Kemphues 1995;Watts et al 1996;Tabuse et al 1998). Subsequent studies have revealed that the gene products are part of an evolutionarily conserved PAR-aPKC system involved in cell polarity in various biological contexts.…”

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