Faculty Bibliography

Plasma phospholipid transfer protein (PLTP) plays an important role in lipoprotein metabolism and reverse cholesterol transport. We have recently reported that plasma PLTP concentration correlates positively with plasma HDL cholesterol (HDL-C) but not with PLTP activity in healthy subjects. We have also shown that PLTP exists as active and inactive forms in healthy human plasma. In the present study, we measured plasma PLTP concentration and PLTP activity, and analyzed the distribution of PLTP in normolipidemic subjects (controls), cholesteryl ester transfer protein (CETP) deficiency, and hypo-alphalipoproteinemia (hypo-ALP). Plasma PLTP concentration was significantly lower (0.7 +/- 0.4 mg/l, mean +/- SD, n = 9, P < 0.001) in the hypo-ALP subjects, and significantly higher (19.5 +/- 4.3 mg/l, n = 17, P < 0.001) in CETP deficiency than in the controls (12.4 +/- 2.3 mg/l, n = 63). In contrast, we observed no significant differences in plasma PLTP activity between controls, hypo-ALP subjects, and CETP deficiency (6.2 +/- 1.3, 6.1 +/- 1.8, and 6.8 +/- 1.2 micro mol/ml/h, respectively). There was a positive correlation between PLTP concentration and plasma HDL-C (r = 0.81, n = 89, P < 0.001). By size exclusion chromatography analysis, we found that the larger PLTP containing particles without PLTP activity (inactive form of PLTP) were almost absent in the plasma of hypo-ALP subjects, and accumulated in the plasma of CETP deficiency compared with those of controls. These results indicate that the differences in plasma PLTP concentrations between hypo-ALP subjects, CETP deficiency, and controls are mainly due to the differences in the amount of the inactive form of PLTP

Cholesteryl ester transfer protein (CETP) deficiency is one of the most important and common causes of hyperalphalipoproteinemia (HALP) in the Japanese. CETP deficiency is thought to be a state of impaired reverse cholesterol transport, which may possibly lead to the development of atherosclerotic cardiovascular disease despite high HDL-cholesterol (HDL-C) levels. Thus, it is important to investigate whether HALP is caused by CETP deficiency. In the present study, we identified two novel missense mutations in the CETP gene among 196 subjects with a marked HALP (HDL-C > or = 2.59 mmol/l = 100 mg/dl). The two missense mutations, L151P (CTC-->CCC in exon 5) and R282C (CGC-->TGC in exon 9), were found in compound heterozygous subjects with D442G mutation, whose plasma CETP levels were significantly lower when compared with those in D442G heterozygous subjects. In COS-7 cells expressing the wild type and mutant CETP, these two mutant CETP showed a marked reduction in the secretion of CETP protein into media (0% and 39% of wild type for L151P and R282C, respectively). These results suggested that two novel missense mutations cause the decreased secretion of CETP protein into circulation leading to HALP. By using the Invader assay for seven mutations, including two novel mutations of the CETP gene, we investigated their frequency among 466 unrelated subjects with HALP (HDL-C > or = 2.07 mmol/l = 80 mg/dl). Two novel mutations were rare, but L151P mutation was found in unrelated subjects with a marked HALP. Furthermore, we demonstrated that CETP deficiency contributes to 61.7% and 31.4% of marked HALP and moderate HALP in the Japanese, respectively

Cytokinesis is the last essential step in the distribution of genetic information to daughter cells and partition of the cytoplasm. In plant cells, various proteins have been found in the phragmoplast, which corresponds to the cytokinetic apparatus, and in the cell plate, which corresponds to a new cross wall, but our understanding of the functions of these proteins in cytokinesis remains incomplete. Reverse genetic analysis of NPK1 MAPKKK (nucleus- and phragmoplast-localized protein kinase 1 mitogen-activated protein kinase kinase kinase) and investigations of factors that might be functionally related to NPK1 have helped to clarify new aspects of the mechanisms of cytokinesis in plant cells. In this review, we summarize the evidence for the involvement of NPK1 in cytokinesis. We also describe the characteristics of a kinesin-like protein and the homologue of a mitogen-activated protein kinase that we identified recently, and we discuss possible relationships among these proteins in cytokinesis

The tobacco mitogen-activated protein kinase kinase kinase NPK1 regulates lateral expansion of the cell plate at cytokinesis. Here, we show that the kinesin-like proteins NACK1 and NACK2 act as activators of NPK1. Biochemical analysis suggests that direct binding of NACK1 to NPK1 stimulates kinase activity. NACK1 is accumulated specifically in M phase and colocalized with NPK1 at the phragmoplast equator. Overexpression of a truncated NACK1 protein that lacks the motor domain disrupts NPK1 concentration at the phragmoplast equator and cell plate formation. Incomplete cytokinesis is also observed when expression of NACK1 and NACK2 is repressed by virus-induced gene silencing and in embryonic cells from Arabidopsis mutants in which a NACK1 ortholog is disrupted. Thus, we conclude that expansion of the cell plate requires NACK1/2 to regulate the activity and localization of NPK1

The new caffeic acid derivative, subulatin (1), was isolated from in vitro cultured liverworts, Jungermannia subulata, Lophocolea heterophylla, and Scapania parvitexta. The structure of 1 involved two caffeic acids, D-glucose, and 2-carboxy-6-(1,2-dihydroxy-ethyl)-4,5-dihydroxy-5,6-dihydro-4H-pyran. The connectivity of those and the absolute stereochemistry of 1 were elucidated on the basis of spectroscopic evidence. The antioxidative activity of 1 was comparable to that of alpha-tocopherol. (2'R)-Phaselic acid (2a) and (-)-9,2''-epiphylloyl-L-malic acid (4) were also isolated from J. subulata and L. heterophylla, respectively. A chiral HPLC analysis of the p-bromobenzoyl-malic acids derived from 2a showed that 2a from J. subulata was unusual (+)-trans-caffeoyl-D-malic acid