Search Results (6)

Protein palmitoylation, a key post-translational modification (PTM) regulating protein transport and function, is catalyzed by palmitoyl transferases (PATs). PATs play vital roles in plant growth, development, and stress responses, yet their characterization in citrus remains limited. This study identified 23 PAT genes (CitPATs) possessing the conserved DHHC domain in the citrus genome through comprehensive genome-wide analysis. Analysis revealed that most CitPAT proteins are hydrophilic, basic, and stable, with significant variations in sequence length. Gene structure and motif analysis confirmed 10 conserved motifs, with the DHHC domain being the most conserved among all 23 members. The CitPAT genes were unevenly distributed across nine chromosomes and exhibit high evolutionary conservation. Promoter analysis identified numerous cis-acting elements associated with abiotic stress and hormone responses, including basic regulatory elements, light-responsive elements, and stress-responsive elements, with light-responsive elements being predominant. Expression profiling during fruit development revealed distinct correlation patterns with citric acid dynamics: CitPAT6, CitPAT18, and CitPAT23 showed positive correlations with acid accumulation, while CitPAT1, CitPAT10, and CitPAT13 exhibited negative correlations. Further RT-qPCR experiments revealed that CitPAT1 and CitPAT10 consistently demonstrated strong negative correlations with citrate content throughout fruit development. This functional diversification suggests roles in regulating citric acid metabolism. These findings provide novel insights into quality formation in facility-cultivated citrus and establish a foundation for understanding PAT-mediated regulation of fruit development. Full article

S-acylation, which includes S-palmitoylation, is the only known reversible lipid-based post-translational protein modification. S-palmitoylation is mediated by palmitoyl acyltransferases (PATs), a family of 23 enzymes commonly referred to as zDHHCs, which catalyze the addition of palmitate to cysteine residues on specific target proteins. Aberrant S-palmitoylation events have been linked to the pathogenesis of multiple human diseases. While there have been advances in elucidating the molecular mechanisms underlying the pathogenesis of various skin conditions, there remain gaps in the knowledge, specifically with respect to the contribution of S-palmitoylation to the maintenance of skin barrier function. Towards this goal, we performed PubMed literature searches relevant to S-palmitoylation in skin to define current knowledge and areas that may benefit from further research studies. Furthermore, to identify alterations in gene products that are S-palmitoylated, we utilized bioinformatic tools such as SwissPalm and analyzed relevant data from publicly available databases such as cBioportal. Since the targeting of S-palmitoylated targets may offer an innovative treatment perspective, we surveyed small molecules inhibiting zDHHCs, including 2-bromopalmitate (2-BP) which is associated with off-target effects, and other targeting strategies. Collectively, our work aims to advance both basic and clinical research on skin barrier function with a focus on zDHHCs and relevant protein targets that may contribute to the pathogenesis of skin conditions such as atopic dermatitis, psoriasis, and skin cancers including melanoma. Full article

Protein S-acyl transferases (PATs) are a family of enzymes that catalyze protein S-acylation, a post-translational lipid modification involved in protein membrane targeting, trafficking, stability, and protein–protein interaction. S-acylation plays important roles in plant growth, development, and stress responses. Here, we report the genome-wide analysis of the PAT family genes in the woodland strawberry (Fragaria vesca), a model plant for studying the economically important Rosaceae family. In total, 21 ‘Asp-His-His-Cys’ Cys Rich Domain (DHHC-CRD)-containing sequences were identified, named here as FvPAT1-21. Expression profiling by reverse transcription quantitative PCR (RT-qPCR) showed that all the 21 FvPATs were expressed ubiquitously in seedlings and different tissues from adult plants, with notably high levels present in vegetative tissues and young fruits. Treating seedlings with hormones indole-3-acetic acid (IAA), abscisic acid (ABA), and salicylic acid (SA) rapidly increased the transcription of most FvPATs. A complementation assay in yeast PAT mutant akr1 and auto-S-acylation assay of one FvPAT (FvPAT19) confirmed its enzyme activity where the Cys in the DHHC motif was required. An AlphaFold prediction of the DHHC and the mutated DHHC155S of FvPAT19 provided further proof of the importance of C155 in fatty acid binding. Together, our data clearly demonstrated that S-acylation catalyzed by FvPATs plays important roles in growth, development, and stress signaling in strawberries. These preliminary results could contribute to further research to understand S-acylation in strawberries and plants in general. Full article

Protein palmitoylation is an ability of the frame of the cell marker protein is one of the most notable reversible changes after translation. However, studies on protein palmitoylation in cotton have not yet been performed. In our current research, the PAT gene family was systematically identified and bioinformatically analyzed in G. arboreum, G. raimondii, G. barbadense and G. hirsutum, and 211 PAT genes were authenticated and classified into six subfamilies. Sixty-nine PAT genes were identified in upland cotton, mainly at the ends of its the 26 chromosomes of upland cotton. The majority of these genes are located in the nucleus of the plant. Gene structure analysis revealed that each member encodes a protein that which contains at least one DHHC structural domain. Cis-acting element analysis indicated that GhPATs genes are mainly involved in hormone production, light response and stress response. Gene expression pattern analysis indicated that most GhPATs genes were differentially expressed upon induction by pathogenic bacteria, drought, salt, hot and cold stresses, and some GhPATs could be induced by multiple abiotic stresses simultaneously. GhPATs genes showed different expression patterns in tissue-specific assays and were found to be preferentially expressed in roots, followed by expression in stems and leaves. Virus-induced gene silencing (VIGS) experiments showed that cotton was significantly less resistant to Verticillium dahliae when GhPAT27 was silenced. We conclude that the GhPAT27 gene, which mediates S-palmitoylation acetylation, may be involved in the regulation of upland cotton resistance to Verticillium wilt (VW). Overall, this work has provided a fundamental framework for understanding the latent capabilities of GhPATs and a solid foundation for molecular breeding and plant pathogen resistance in cotton. Full article

Lipid modification of viral proteins with fatty acids of different lengths (S-acylation) is crucial for virus pathogenesis. The reaction is catalyzed by members of the DHHC family and proceeds in two steps: the autoacylation is followed by the acyl chain transfer onto protein substrates. The crystal structure of human DHHC20 (hDHHC20), an enzyme involved in the acylation of S-protein of SARS-CoV-2, revealed that the acyl chain may be inserted into a hydrophobic cavity formed by four transmembrane (TM) α-helices. To test this model, we used molecular dynamics of membrane-embedded hDHHC20 and its mutants either in the absence or presence of various acyl-CoAs. We found that among a range of acyl chain lengths probed only C16 adopts a conformation suitable for hDHHC20 autoacylation. This specificity is altered if the small or bulky residues at the cavity’s ceiling are exchanged, e.g., the V185G mutant obtains strong preferences for binding C18. Surprisingly, an unusual hydrophilic ridge was found in TM helix 4 of hDHHC20, and the responsive hydrophilic patch supposedly involved in association was found in the 3D model of the S-protein TM-domain trimer. Finally, the exchange of critical Thr and Ser residues in the spike led to a significant decrease in its S-acylation. Our data allow further development of peptide/lipid-based inhibitors of hDHHC20 that might impede replication of Corona- and other enveloped viruses. Full article

Selenoprotein K (SELENOK) is a selenocysteine (Sec)-containing protein localized in the endoplasmic reticulum (ER) membrane where it interacts with the DHHC6 (where single letter symbols represent Asp-His-His-Cys amino acids) enzyme to promote protein acyl transferase (PAT) reactions. PAT reactions involve the DHHC enzymatic capture of palmitate via a thioester bond to cysteine (Cys) residues that form an unstable palmitoyl-DHHC intermediate, followed by transfer of palmitate to Cys residues of target proteins. How SELENOK facilitates this reaction has not been determined. Splenocyte microsomal preparations from wild-type mice versus SELENOK knockout mice were used to establish PAT assays and showed decreased PAT activity (~50%) under conditions of SELENOK deficiency. Using recombinant, soluble versions of DHHC6 along with SELENOK containing Sec₉₂, Cys₉₂, or alanine (Ala₉₂), we evaluated the stability of the acyl-DHHC6 intermediate and its capacity to transfer the palmitate residue to Cys residues on target peptides. Versions of SELENOK containing either Ala or Cys residues in place of Sec were equivalently less effective than Sec at stabilizing the acyl-DHHC6 intermediate or promoting PAT activity. These data suggest that Sec₉₂ in SELENOK serves to stabilize the palmitoyl-DHHC6 intermediate by reducing hydrolyzation of the thioester bond until transfer of the palmitoyl group to the Cys residue on the target protein can occur. Full article