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Animals subjected to dietary restriction (DR) have reduced body size, low fecundity, slower development, lower fat content and longer life span. We identified lamin as a regulator of multiple dietary restriction phenotypes. Downregulation of lmn-1, the single Caenorhabditis elegans lamin gene, increased animal size and fat content specifically in DR animals. The LMN-1 protein acts in the mTOR pathway, upstream of RAPTOR and S6 kinase β1 (S6K), a key component of and target of the mechanistic target of rapamycin (mTOR) complex 1 (mTORC1), respectively. DR excludes the mTORC1 activator RAGC-1 from the nucleus. Downregulation of lmn-1 restores RAGC-1 to the nucleus, a necessary step for the activation of the mTOR pathway. These findings further link lamin to metabolic regulation. [ABSTRACT FROM AUTHOR]

The mechanistic target of rapamycin (mTOR) is an evolutionary conserved protein with a serine/ threonine kinase activity that regulates cell growth, proliferation, motility, survival, protein synthesis, autophagy and transcription. It is embedded in 2 large protein complexes: mTORC1 and mTORC2. Regulation of specific mTOR pathway functions depends on multiple GTPases, that act either as regulators of mTOR protein complexes, coupling energy availability with mTORC1 activity, or as downstream effectors of both mTORC1 and mTORC2. In this commentary, we highlight the advantages of studying the mTOR pathway in C. elegans, including the subcellular localization of the signaling pathway components and the animal phenotypes following tissue specific protein overexpression or knockdown. One important regulator that is not limited to the mTOR pathway is RHEB. We discuss in vitro and in vivo data suggesting that RHEB can function as an inhibitor of mTOR when not bound to GTP. RHEB-1 itself is regulated by Rab GDP dissociation inhibitor b, which directly binds to ATX-2. We also highlight the roles of these proteins in dietary restriction-depended reduction in animal size and fat content. [ABSTRACT FROM AUTHOR]

Specific mutations in human LMNA or loss of ZMPSTE26 activity cause abnormal processing of lamin A and early aging diseases, including Hutchinson Gilford progeria syndrome (HGPS). HGPS fibroblasts in culture undergo age-dependent progressive changes in nuclear architecture. Treating these cells with farnesyl transferase inhibitors (FTIs) reverse these nuclear phenotypes and also extend lifespan of mice HGPS models. Dermal cells derived from healthy old humans also accumulate the abnormally processed lamin A. However, the effect of FTIs on normal aging cells was not tested. Aging adult C. elegans cells show changes in nuclear architecture similar to HGPS fibroblasts and down regulating lamin expression in adult C. elegans reduces their lifespan. Here, we show that nuclei of adult C. elegans, in which lamin is down-regulated, have similar phenotypes to normal aging nuclei, but at an earlier age. We further show that treating adult C. elegans with the FTI gliotoxin reverses nuclear phenotypes and improves motility of aging worms. However, the average lifespan of the gliotoxin-treated animals was similar to that of untreated animals. These results suggest that lamins are involved in the process of normal aging in C. elegans. Cell Motil. Cytoskeleton 2009. © 2009 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Objective Materials and Methods Results Conclusions To evaluate the efficacy of recombinant psoriasin as a novel treatment for oral candidiasis by eliminating Candida albicans growth on polymethyl methacrylate denture base.Recombinant psoriasin protein was expressed and purified from E. coli, and Candida growth was monitored in vitro with varying concentrations of psoriasin. Subsequently, denture‐base polymethyl methacrylate was immersed in psoriasin's solution or voriconazole, and fungal growth on the acrylic base and in the medium was examined by scanning electron microscopy and optical density, respectively. Cellular viability of HeLa and human gingival fibroblast cells treated with psoriasin was measured by methylene blue assay.The findings reveal an effective antifungal activity of psoriasin, completely inhibiting Candida albicans growth in RPMI at a protein concentration above 400 nM. Immersing the polymethyl methacrylate with 50 μM psoriasin completely eradicates fungal growth. Psoriasin has low cytotoxicity in HeLa cells at a concentration higher than 12 μM and no toxic effect on human gingival fibroblasts.This study marks psoriasin as an effective alternative to conventional antifungal treatments for denture stomatitis and a safe alternative to chemical antifungals in dental medicine and beyond. [ABSTRACT FROM AUTHOR]

The eukaryotic genome inside the nucleus is enveloped by two membranes, the Outer Nuclear Membrane (ONM) and the Inner Nuclear Membrane (INM). Tethered to the INM is the nuclear lamina, a fibrillar network composed of lamins-the nuclear intermediate filaments, and membrane associated proteins. The nuclear lamina interacts with several nuclear structures, including chromatin. As most nuclear functions, including regulation of gene expression, chromosome segregation and duplication as well as nuclear structure, are highly conserved in metazoans, the Caenorhabditis elegans nematode serves as a powerful model organism to study nuclear processes and architecture. This translucent organism can easily be observed under a microscope as a live embryo, larvae and even adult. Here we will review the data on nuclear lamina composition and functions gathered from studies using C. elegans model organisms: We will discuss genome spatial organization and its contribution to gene expression. We will review both the interaction between the cytoplasm and the nucleus and mechanotransduction mechanism. Finally, we will discuss disease causing mutation in nuclear lamins, including the use of this animal model in diseases research., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Protein function often depends on assemblies and interactions. These show complex spatial and temporal organization within the cell. Analysis of protein function can be greatly assisted by grouping proteins with their neighbors. Rather than relying on affinity, proximity labeling targets proteins proximal to the target of interest. We describe a protocol for antibody-guided deposition of tags in fixed and permeabilized cell lines and primary human tissue samples.