Underwood K W, Song C, Kriz R W, Chang X J, Knopf J L, Lin L L
Small Molecule Drug Discovery Group, Genetics Institute, Cambridge, Massachusetts 02140, USA.
J Biol Chem. 1998 Aug 21;273(34):21926-32. doi: 10.1074/jbc.273.34.21926.
We report the cloning and characterization of a novel membrane-bound, calcium-independent PLA2, named cPLA2-gamma. The sequence encodes a 541-amino acid protein containing a domain with significant homology to the catalytic domain of the 85-kDa cPLA2 (cPLA2-alpha). cPLA2-gamma does not contain the regulatory calcium-dependent lipid binding (CaLB) domain found in cPLA2-alpha. However, cPLA2-gamma does contain two consensus motifs for lipid modification, a prenylation motif (-CCLA) at the C terminus and a myristoylation site at the N terminus. We present evidence that the isoprenoid precursor [3H]mevalonolactone is incorporated into the prenylation motif of cPLA2-gamma. Interestingly, cPLA2-gamma demonstrates a preference for arachidonic acid at the sn-2 position of phosphatidylcholine as compared with palmitic acid. cPLA2-gamma encodes a 3-kilobase message, which is highly expressed in heart and skeletal muscle, suggesting a specific role in these tissues. Identification of cPLA2-gamma reveals a newly defined family of phospholipases A2 with homology to cPLA2-alpha.
我们报告了一种名为cPLA2-γ的新型膜结合、钙非依赖性磷脂酶A2（PLA2）的克隆和特性分析。该序列编码一个541个氨基酸的蛋白质，其包含一个与85 kDa的cPLA2（cPLA2-α）催化结构域具有显著同源性的结构域。cPLA2-γ不包含在cPLA2-α中发现的调节性钙依赖性脂质结合（CaLB）结构域。然而，cPLA2-γ确实包含两个脂质修饰的共有基序，一个位于C末端的异戊二烯化基序（-CCLA）和一个位于N末端的肉豆蔻酰化位点。我们提供的证据表明类异戊二烯前体[3H]甲羟戊酸内酯被掺入cPLA2-γ的异戊二烯化基序中。有趣的是，与棕榈酸相比，cPLA2-γ在磷脂酰胆碱的sn-2位置对花生四烯酸表现出偏好。cPLA2-γ编码一个3千碱基的信息，在心脏和骨骼肌中高度表达，表明其在这些组织中具有特定作用。cPLA2-γ的鉴定揭示了一个与cPLA2-α具有同源性的新定义的磷脂酶A2家族。
