The glycerol-3-phosphate acyltransferase PLAT2 functions in the generation of DHA-rich glycerolipids in Aurantiochytrium limacinum F26-b
The glycerol-3-phosphate acyltransferase PLAT2 functions in the generation of DHA-rich glycerolipids in Aurantiochytrium limacinum F26-b
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DOI：
10.1371/journal.pone.0211164
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发表时间：
2019-01
期刊：
影响因子：
3.7
通讯作者：
Eri Nutahara;Eriko Abe;Shinya Uno;Yohei Ishibashi;Takashi Watanabe;M. Hayashi;N. Okino;Makoto Ito
中科院分区：
文献类型：
--
作者：
Eri Nutahara;Eriko Abe;Shinya Uno;Yohei Ishibashi;Takashi Watanabe;M. Hayashi;N. Okino;Makoto Ito
破囊壶菌具有二十二碳六烯酸（DHA，22：6 n-3）作为三酰甘油（TG）和磷脂酰胆碱（PC）的酰基链，其中一些含有多个DHA。然而，很少有人知道这些DHA丰富的甘油脂是如何产生的破囊壶菌。在这项研究中，我们确定了在Aurantiochytrium limacinum F26-B作为一个甘油-3-磷酸（G3 P）酰基转移酶（GPAT）的基因在芽殖酵母异源表达的PLAT 2。随后，我们发现在A. limacinum，导致含DHA的溶血磷脂酸（LPA 22：6）减少。相反，PLAT 2的过表达增加了GPAT活性和LPA 22：6。这些结果表明PLAT 2是一种GPAT，在体内以及体外将DHA转移至G3 P。PLAT 2基因的过表达增加了含有两个DHA的二酰基甘油（DG 44：12）的产生，随后增加了含有三个DHA的TG（TG 66：18）、含有两个DHA的TG（TG 60：12）和含有两个DHA的PC（PC 44：12）。然而，PLAT 2的过表达并不增加无DHA的DG（DG 32：0），其优先转化为三个含16：0的TG（TG 48：0），而不是两个含16：0的PC（PC 32：0）。总的来说，我们发现富含DHA的甘油酯是由前体LPA 22：6产生的，LPA 22：6是通过A中的PLAT 2将DHA并入G3 P而产生的。利马辛
Thraustochytrids possess docosahexaenoic acid (DHA, 22:6n-3) as acyl chain(s) of triacylglycerol (TG) and phosphatidylcholine (PC), some of which contain multiple DHAs. However, little is known about how these DHA-rich glycerolipids are produced in thraustochytrids. In this study, we identified PLAT2 in Aurantiochytrium limacinum F26-b as a glycerol-3-phosphate (G3P) acyltransferase (GPAT) by heterologous expression of the gene in budding yeast. Subsequently, we found that GPAT activity was reduced by disruption of the PLAT2 gene in A. limacinum, resulting in a decrease in DHA-containing lysophosphatidic acid (LPA 22:6). Conversely, overexpression of PLAT2 increased both GPAT activity and LPA 22:6. These results indicate that PLAT2 is a GPAT that transfers DHA to G3P in vivo as well as in vitro. Overexpression of the PLAT2 gene increased the production of a two DHA-containing diacylglycerol (DG 44:12), followed by an increase in the three DHA-containing TG (TG 66:18), two-DHA-containing TG (TG 60:12), and two DHA-containing PC (PC 44:12). However, overexpression of PLAT2 did not increase DHA-free DG (DG32:0), which was preferentially converted to three 16:0-containing TG (TG 48:0) but not two 16:0-containing PC (PC 32:0). Collectively, we revealed that DHA-rich glycerolipids are produced from a precursor, LPA 22:6, which is generated by incorporating DHA to G3P by PLAT2 in the A. limacinum.