Rua R et al. (2023) Immunity "Pathogen metabolite checkpoint: NHR on guard."

Rua R, Pujol N

[Immunity, 2023]

How can beneficial microorganisms be distinguished from pathogenic ones? In this issue of Immunity, Peterson et al. discovered that a specific phenazine, which is part of a family of toxic metabolites expressed by pathogenic bacteria, is detected by Caenorhabditis elegans by directly binding to a nuclear hormone receptor, promoting the expression of detoxifying enzymes and immunity-related genes, thus protecting the worm.

Tse SY et al. (2023) STAR Protoc "Protocol to assess receptor-ligand binding in C. elegans using adapted thermal shift assays."

Tse SY, Pukkila-Worley R

[STAR Protoc, 2023]

The Caenorhabditis elegans genome encodes a greatly expanded number of nuclear hormone receptors, many of which remain orphaned. Here, we present a protocol to assess ligand-receptor binding in C. elegans using an adapted cellular thermal shift assay and isothermal dose response. We describe steps for growing C. elegans and preparing lysates and compounds. We also detail how to perform and quantify these assays. This protocol can be used to study any soluble receptor. For complete details on the use and execution of this protocol, please refer to Peterson et al. (2023).¹.

Osman MA et al. (1998) J Cell Biol "Iqg1p, a yeast homologue of the mammalian IQGAPs, mediates cdc42p effects on the actin cytoskeleton."

Cerione RA, Osman MA

[J Cell Biol, 1998]

The Rho-type GTPase Cdc42p has been implicated in diverse cellular functions including cell shape, cell motility, and cytokinesis, all of which involve the reorganization of the actin cytoskeleton. Targets of Cdc42p that interface the actin cytoskeleton are likely candidates for mediating cellular activities. In this report, we identify and characterize a yeast homologue for the mammalian IQGAP, a cytoskeletal target for Cdc42p. The yeast IQGAP homologue, designated Iqg1p, displays a two-hybrid interaction with activated Cdc42p and coimmunoprecipitates with actin filaments. Deletion of IQG1 results in a temperature-sensitive lethality and causes aberrant morphologies including elongated and round multinucleated cells. This together with its localization at the mother-bud neck, suggest that Iqg1p promotes budding and cytokinesis. At restrictive temperatures, the vacuoles of the mutant cells enlarge and vesicles accumulate in the bud. Interestingly, Iqg1p shows two-hybrid interactions with the ankyrin repeat-containing protein, Akr1p (Kao, L.-R., J. Peterson, J. Ruiru, L. Bender, and A. Bender. 1996. Mol. Cell. Biol. 16:168-178), which inhibits pheromone signaling and appears to promote cytokinesis and/or trafficking. We also show two-hybrid interactions between Iqg1p and Afr1p, a septin-binding protein involved in projection formation (Konopka, J.B., C. DeMattei, and C. Davis. 1995. Mol. Cell. Biol. 15:723-730). We propose that Iqg1p acts as a scaffold to recruit and localize a protein complex involved in actin-based cellular functions and thus mediates the regulatory effects of Cdc42p on the actin cytoskeleton.