Diacylglycerol kinase γ is a novel anionic phospholipid binding protein with a selective binding preference.
There are ten isozymes of diacylglycerol kinase (DGK), and they regulate diverse patho-physiological functions. Here, we investigated the lipid-binding properties of DGK isozymes using protein-lipid overlay and liposome-binding assays. DGKγ showed a strong binding activity compared with other DGK isozymes for phosphatidic acid (PA) among the various glycerophospholipids tested. However, DGKγ failed to interact with DG and lyso-PA. Moreover, the isozyme was capable of binding to ceramide-1-phosphate but not to ceramide or sphingosine-1-phosphate. The isozyme bound more strongly to PA containing unsaturated fatty acid than to PA having only saturated fatty acid. An analysis using a series of deletion mutants of DGKγ revealed that the N-terminal region, which contains a recoverin homology domain and EF-hand motifs, is responsible for the PA binding activity of DGKγ. Taken together, these results indicate that DGKγ is an anionic phospholipid binding protein that preferably interacts with a small highly charged head group that is very close to the glycerol or sphingosine backbone.
Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
Ena
E
Takeshita
Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
Aiko
A
Kume
Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
Yuki
Y
Maeda
Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
Hiromichi
H
Sakai
Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan. Electronic address: sakane@faculty.chiba-u.jp.
Fumio
F
Sakane
D000818:Animals; D000838:Anions / Q000378:metabolism; D001665:Binding Sites; D019556:COS Cells; D002518:Ceramides / Q000378:metabolism; D002522:Chlorocebus aethiops; D019852:Diacylglycerol Kinase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008246:Lysophospholipids / Q000378:metabolism; D010712:Phosphatidic Acids / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D011485:Protein Binding; D013110:Sphingosine / Q000031:analogs & derivatives / Q000378:metabolism; D014162:Transfection
D000838:Anions; D002518:Ceramides; D007527:Isoenzymes; D008246:Lysophospholipids; D010712:Phosphatidic Acids; D010743:Phospholipids; C065576:ceramide 1-phosphate; C060506:sphingosine 1-phosphate; D019852:Diacylglycerol Kinase; D013110:Sphingosine
Ceramide-1-phosphate; Diacylglycerol kinase; EF-hand; Phosphatidic acid; Unsaturated fatty acid