α/β-Hydrolase Domain-Containing 6 (ABHD6)- A Multifunctional Lipid Hydrolase

A α-L-rhamnosidase from Echinacea purpurea endophyte Simplicillium sinense EFF1 and its application in production of Calceorioside B

Calceorioside B, a multifunctional phenylethanol glycosides (PhGs) derivative, exhibits a variety of notable properties, such as antithrombotic, anti-tumorigenic, anti-neocoronavirus, anti-inflammatory, and neuroprotective effects. However, the large-scale production of calceorioside B is routinely restricted by its existence as an intermediary compound derived from plants, and still unachieved through excellent and activity chemical synthesis. Here, a total of 51 fungal endophytes were isolated from four PhGs-producing plants, and endophyte Simplicillium sinense EFF1 from Echinacea purpurea was identified with the ability to de-rhamnosing isoacteoside to generate calceorioside B. According to the RNA-transcription of EFF1 under the various substrates, a key gene CL1206.Contig2 that undertakes the hydrolysis function was screened out and charactered by heterologous expression. The sequence alignment, phylogenetic tree construction and substrate specificity analysis revealed that CL1206 was a novel α-L-rhamnosidase that belongs to the glycosyl hydrolase family 78 (GH78). The optimum catalytic conditions for CL1206 were at pH 6.5 and 55 °C. Finally, the enzyme-catalyzed approach to produce calceorioside B from 50 % crude isoacteoside extract was explored and optimized, with the maximum conversion rate reaching 69.42 % and the average producing rate reaching 0.37 g-1.L-1.h-1, which offered a great biocatalyst for potential industrial calceorioside B production. This is the first case for microorganism and rhamnosidase to show the hydrolysis ability to caffeic acid-modified PhGs.

ABHD6 suppresses colorectal cancer progression via AKT signaling pathway

Colorectal cancer (CRC) continues to be a prevalent malignancy, posing a significant risk to human health. The involvement of alpha/beta hydrolase domain 6 (ABHD6), a serine hydrolase family member, in CRC development was suggested by our analysis of clinical data. However, the role of ABHD6 in CRC remains unclear. This study seeks to elucidate the clinical relevance, biological function, and potential molecular mechanisms of ABHD6 in CRC. We investigated the role of ABHD6 in clinical settings, conducting proliferation, migration, and cell cycle assays. To determine the influence of ABHD6 expression levels on Oxaliplatin sensitivity, we also performed apoptosis assays. RNA sequencing and KEGG analysis were utilized to uncover the potential molecular mechanisms of ABHD6. Furthermore, we validated its expression levels using Western blot and reactive oxygen species (ROS) detection assays. Our results demonstrated that ABHD6 expression in CRC tissues was notably lower compared to adjacent normal tissues. This low expression correlated with a poorer prognosis for CRC patients. Moreover, ABHD6 overexpression impeded CRC cell proliferation and migration while inducing G0/G1 cell cycle arrest. In vivo experiments revealed that downregulation of ABHD6 resulted in an increase in tumor weight and volume. Mechanistically, ABHD6 overexpression inhibited the activation of the AKT signaling pathway and decreased ROS levels in CRC cells, suggesting the role of ABHD6 in CRC progression via the AKT signaling pathway. Our findings demonstrate that ABHD6 functions as a tumor suppressor, primarily by inhibiting the AKT signaling pathway. This role establishes ABHD6 as a promising prognostic biomarker and a potential therapeutic target for CRC patients.

PNPLA-mediated lipid hydrolysis and transacylation - At the intersection of catabolism and anabolism

Patatin-like phospholipase domain containing proteins (PNPLAs) play diverse roles in lipid metabolism. In this review, we focus on the enzymatic properties and predicted 3D structures of PNPLA1-5. PNPLA2-4 exert both catabolic and anabolic functions. Whereas PNPLA1 is predominantly expressed in the epidermis and involved in sphingolipid biosynthesis, PNPLA2 and 4 are ubiquitously expressed and exhibit several enzymatic activities, including hydrolysis and transacylation of various (glycero-)lipid species. This review summarizes known biological roles for PNPLA-mediated hydrolysis and transacylation reactions and highlights open questions concerning their physiological function.

Chemoproteomic Profiling of Erastin-Interacting Proteins

Ferroptosis is an iron-related cell death caused by irregular lipid peroxidation that has been implicated with a variety of disease. Erastin is a canonical ferroptosis inducer that is known to function by inhibiting system Xc- and cystine transport; however, the global interactome of erastin in cells remains unexplored. In this work, we employed a quantitative chemoproteomic approach to profile direct interacting proteins of erastin in living cells using a multifunctional photo-cross-linking probe. A number of novel erastin-interacting proteins were identified, including a serine hydrolase, ABHD6, whose overexpression showed a potentiating impact on ferroptosis. Further biochemical experiments revealed that erastin can allosterically activate ABHD6's activity to produce more arachidonic acids and elevate the level of lipid reactive oxygen species. Collectively, our work provided a global portrait of erastin-interacting proteins and discovered ABHD6 as a new ferroptosis regulator.