Crystal structure of human brain-type fatty acid-binding protein FABP7 complexed with palmitic acid

Evaluation of AlphaFold3 for the fatty acids docking to human fatty acid-binding proteins

Human fatty acid-binding proteins (FABPs) are involved in many aspects of lipid metabolism, such as the uptake, transport, and storage of lipophilic molecules, as well as cellular functions. Understanding how FABPs recognize fatty acids (FAs) is crucial for identifying FABP function and applications, such as in inhibitor design or biomarker development. The recently developed AlphaFold3 (AF3) demonstrates significantly higher accuracy than other prediction tools, particularly in predicting protein-ligand interactions with state-of-the-art docking tools. Studies on whether AF3 can be used to identify the FAs of FABP are lacking. To assess the accuracy of FA docking to FABPs using AF3, models of FA docked into FABP generated using AF3 were compared with experimentally determined FA-bound FABP structures. FA ligands in AF3 structures docked reliably into the FA-binding pocket of FABPs; however, the detailed binding configuration of most FA ligands docked into FABPs and the interaction between FA and FABP determined using AF3 and experimentally differed. These results will aid in understanding FA docking to FABPs and other FA-binding proteins using AF3.

Importance of fatty acid binding proteins in cellular function and organismal metabolism

Fatty acid binding proteins (Fabps) are small soluble proteins that are abundant in the cytosol. These proteins are known to bind a myriad of small hydrophobic molecules and have been postulated to serve a variety of roles, yet their precise functions have remained an enigma over half a century of study. Here, we consider recent findings, along with the cumulative findings contributed by many laboratories working on Fabps over the last half century, to synthesize a new outlook for what functions Fabps serve in cells and organisms. Collectively, the findings illustrate that Fabps function as versatile multi-purpose devices serving as sensors, conveyors and modulators to enable cells to detect and handle a specific class of metabolites, and to adjust their metabolic capacity and efficiency.

Gene expression response to Salmonella Typhimurium in the cecal tonsil reveals a potential mechanism of resistance in chickens

Salmonella has been one of the most important factors restricting the development of the poultry industry and also poses great threat to public health. To get insight into molecular alterations that occur during bacterial infection, we sequenced the cecal tonsil transcriptome in 2 chicken breeds (Beijing-You and Cobb) known to have differing resistance to Salmonella. The 28-day-old chickens were orally challenged by 1.83 × 1011 CFU Salmonella Typhimurium, and the cecal tonsil transcriptome was sequenced 3 d postinfection. Analysis identified 201 and 170 differentially expressed genes response to Salmonella in 2 chicken breeds, respectively. They were involved in the Toll-like receptor signaling pathway and activated the production of pro-inflammatory cytokines and chemokines. The protein-protein interaction (PPI) network suggested MMP9 as a crucial protein that may be involved in extracellular matrix breakdown and leukocyte migration in the resistant breed (Beijing-You). Meanwhile, in susceptible chickens (Cobb), ACOD1 was the key gene in the PPI network and might promote the expression of genes related to oxidative stress response and gastrointestinal tract function. These findings provide insight into the differing resistance of these 2 chicken breeds.

Molecular Characteristics of the Fatty-Acid-Binding Protein (FABP) Family in Spirometra mansoni-A Neglected Medical Tapeworm

The plerocercoid larva of the tapeworm Spirometra mansoni can parasitize humans and animals, causing serious parasitic zoonosis. The molecular characteristics and adaptive parasitism mechanism of Spirometra tapeworms are still unknown. In this study, 11 new members of the fatty-acid-binding protein (FABP) family were characterized in S. mansoni. A clustering analysis showed 11 SmFABPs arranged into two groups, and motif patterns within each group had similar organizations. RT-qPCR showed that SmFABPs were highly expressed in the adult stage, especially in gravid proglottid. A high genetic diversity of SmFABPs and relative conservation of FABPs in medical platyhelminthes were observed in the phylogenetic analysis. Immunolocalization revealed that natural SmFABP is mainly located in the tegument and parenchymal tissue of the plerocercoid and the uterus, genital pores, and cortex of adult worms. rSmFABP can build a more stable holo form when binding with palmitic acid to protect the hydrolytic sites of the protein. A fatty acid starvation induction test suggested that SmFABP might be involved in fatty acid absorption, transport, and metabolism in S. mansoni. The findings in this study will lay the foundation to better explore the underlying mechanisms of FABPs involved in Spirometra tapeworms as well as related taxa.

The Multifunctional Family of Mammalian Fatty Acid-Binding Proteins

Fatty acid-binding proteins (FABPs) are small lipid-binding proteins abundantly expressed in tissues that are highly active in fatty acid (FA) metabolism. Ten mammalian FABPs have been identified, with tissue-specific expression patterns and highly conserved tertiary structures. FABPs were initially studied as intracellular FA transport proteins. Further investigation has demonstrated their participation in lipid metabolism, both directly and via regulation of gene expression, and in signaling within their cells of expression. There is also evidence that they may be secreted and have functional impact via the circulation. It has also been shown that the FABP ligand binding repertoire extends beyond long-chain FAs and that their functional properties also involve participation in systemic metabolism. This article reviews the present understanding of FABP functions and their apparent roles in disease, particularly metabolic and inflammation-related disorders and cancers.