文章基本信息

标题：Phosphatidylserine synthase 2: high efficiency for synthesizing phosphatidylserine containing docosahexaenoic acid
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作者：Atsuko Kakio Kimura ; Hee-Yong Kim
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：2013
卷号：54
期号：1
页码：214-222
DOI：10.1194/jlr.M031989
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：Phosphatidylserine (PS), the major anionic phospholipid in eukaryotic cell membranes, is synthesized by the integral membrane enzymes PS synthase 1 (PSS1) and 2 (PSS2). PSS2 is highly expressed in specific tissues, such as brain and testis, where docosahexaenoic acid (DHA, 22:6n-3) is also highly enriched. The purpose of this work was to characterize the hydrocarbon-chain preference of PSS2 to gain insight on the specialized role of PSS2 in PS accumulation in the DHA-abundant tissues. Flag-tagged PSS2 was expressed in HEK cells and immunopurified in a functionally active form. Purified PSS2 utilized both PE plasmalogen and diacyl PE as substrates. Nevertheless, the latter was six times better utilized, indicating the importance of an ester linkage at the sn-1 position. Although no sn-1 fatty acyl preference was noted, PSS2 exhibited significant preference toward DHA compared with 18:1 or 20:4 at the sn-2 position. Preferential production of DHA-containing PS (DHA-PS) was consistently observed with PSS2 purified from a variety of cell lines as well as with microsomes from mutant cells in which PS synthesis relies primarily on PSS2. These findings suggest that PSS2 may play a key role in PS accumulation in brain and testis through high activity toward DHA-containing substrates that are abundant in these tissues.
关键词：mass spectrometry ; plasmalogen ; membranes ; omega-3 fatty acids ; phospholipids