Role of Different Members of the AGPAT Gene Family in Milk Fat Synthesis in Bubalus bubalis

Abstract

During triacylglycerol synthesis, the acylglycerol-3-phosphate acyltransferase (AGPAT) family catalyzes the conversion of lysophosphatidic acid to phosphatidic acid and the acylation of sn-2 fatty acids. However, the catalytic activity of different AGPAT members is different. Therefore, this study aimed to investigate the mechanism through which different AGPATs affect the efficiency of TAG synthesis and fatty acid composition. The conservation of amino acid sequences and protein domains of the AGPAT family was analyzed, and the functions of AGPAT1, AGPAT3, and AGPAT4 genes in buffalo mammary epithelial cells (BMECs) were studied using RNA interference and gene overexpression. Prediction of the protein tertiary structure of the AGPAT family demonstrated that four conservative motifs (motif1, motif2, motif3, and motif6) formed a hydrophobic pocket in AGPAT proteins, except AGPAT6. According to cytological studies, AGPAT1, AGPAT3, and AGPAT4 were found to promote the synthesis and fatty acid compositions of triacylglycerol, especially UFA compositions of triacylglycerol, by regulating ACSL1, FASN, GPAM, DGAT2, and PPARG gene expression. This study provides new insights into the role of different AGPAT gene family members involved in TAG synthesis, and a reference for improving the fatty acid composition of milk.

A Characterization and Functional Analysis of Peroxisome Proliferator-Activated Receptor Gamma Splicing Variants in the Buffalo Mammary Gland

“…Triacylglycerol (TAG), which comprises 98% of the fat in buffalo milk, is synthesized from fatty acids and glycerin by enzymes such as GPAT, AGPAT, LPIN, and DGAT [ 32 ]. Among them, GPAM catalyzes glycerol-3-phosphate to produce lysophosphatidic acid, AGPAT catalyzes the conversion of LPA to phosphatidic acid, then further dephosphorylates it to form DAG, and then catalyzes it with DGAT to produce triglyceride [ 16 ]. In this study, we found that after PPARγ-X17 overexpression, the expression of ACSL1 , CD36 , and GPAM was significantly increased, while the expression of ACACA was found to be significantly decreased ( Figure 6 ), suggesting that PPARγ-X17 overexpression can regulate fatty acid transport and triglyceride synthesis but does not affect the de novo synthesis of fatty acids.…”

“…Characteristic analysis of the PPARG isoforms was performed referring to the previous reports [ 15 , 16 ]. In brief, a neighbor-joining phylogenetic tree was constructed in MEGA11 (v11.0.11).…”

Whole-genome resequencing of native and imported dairy goat identifies genes associated with productivity and immunity

“…ACADS , AGPAT4 , PTDSS2 , and SMOX are mainly involved in lipid metabolism and amino acid metabolism pathways. ACADS is involved in the fatty acid metabolism pathway ( 47 ), AGPAT4 promotes triacylglycerol synthesis and fatty acid composition ( 48 ), PTDSS2 is involved in the glycerophospholipid metabolism pathway ( 49 ), and SMOX is a candidate gene for growth, carcass composition traits, and milk production traits ( 50 , 51 ). In addition, previously reported traits associated with immunity ( BPIFA3 , LRRC66 ) ( 52 , 53 ), coat color ( ASIP ) ( 54 ), milk composition ( CSN1S1 , DGAT2 , PLIN4 , PLIN5 , IGF2R ) ( 55 ), and milk production ( AMPD1 ) ( 56 ) were also found in imported breeds.…”