and these amino acids bind to active site of protein kinase C to inhibit its activity as
pseudo-substrate [23, 24]. When cell is activated in signaling process, free protein
kinase C of inactive form is bound to plasma membrane and then active site of
protein kinase C is opened by conformational change of protein kinase C [25]. Calcium ions and phospholipids play important roles in the activating mechanism of
protein kinase C. Negatively charged phosphatidylserine is hydrated in aqueous
environment. The hydrated water molecule is replaced by calcium ion when calcium
ion is added, and surface of phosphatidylserine becomes hydrophobic. This change
may be important for interaction between lipid membrane and hydrophobic region of
cytosolic protein. In addition, some enzymes such as diacylglycerol kinase, calactin,
endonexin, calmcimedin, synexin and calelectin bind membrane in calcium ion
dependent manner [26]. Protein kinase C and related protein induced segregation of
acidic phospholipid [27, 28]. And using peptide mimicking pseudo-substrate
(Acrylodan-labeled MARKS) in binary liposomal system of phosphatidylcholine
and NBS-labeled phosphatidylserine, phase separation induced by the peptide was
reported [29]. Induction of hexagonal II structure and cubic structure was reported as
effects of diacylglycerol on physical property of lipid membranes [30]. From these
results, supposed mechanism of lipid second messenger inducing signaling process is
shown in Fig. 6.4. And lipid second messenger in signaling system of cell was
reviewed by Makowsky and O.M. Rosen [24]. On the other hand, Generation of
phosphatidic acids makes possible to translocate calcium ions through lipid membrane as shown in Fig. 6.5 [31].
6.5 Non-bilayer Forming Lipids and Function
of Biomembrane
Although basic structure of biomembrane is lipid bilayer membrane as assembly of
lipid molecules, the lipid membrane shows polymorphism in its structure and
physical property. Lipid molecule of cone shape prefers non-bilayer structure such
as hexagonal II and lipidic particle. And role of non-bilayer structure on function of
biomembrane was studied.
6.5.1 Membrane Structure Formed by Non-bilayer Forming
Lipids
Basic concept of biomembrane was established by ‘fluid mosaic membrane model’
proposed by Singer and Nicolson [32], but formation of non-bilayer structure under
a condition was observed by
31 P-NMR in 1978 [30], and then observed by freezefractured electron microscope [33]. From these results, relationship between
non-bilayer forming lipids and non-bilayer structure such as hexagonal II structure
6.5 Non-bilayer Forming Lipids and Function of Biomembrane
87
pseudo-substrate [23, 24]. When cell is activated in signaling process, free protein
kinase C of inactive form is bound to plasma membrane and then active site of
protein kinase C is opened by conformational change of protein kinase C [25]. Calcium ions and phospholipids play important roles in the activating mechanism of
protein kinase C. Negatively charged phosphatidylserine is hydrated in aqueous
environment. The hydrated water molecule is replaced by calcium ion when calcium
ion is added, and surface of phosphatidylserine becomes hydrophobic. This change
may be important for interaction between lipid membrane and hydrophobic region of
cytosolic protein. In addition, some enzymes such as diacylglycerol kinase, calactin,
endonexin, calmcimedin, synexin and calelectin bind membrane in calcium ion
dependent manner [26]. Protein kinase C and related protein induced segregation of
acidic phospholipid [27, 28]. And using peptide mimicking pseudo-substrate
(Acrylodan-labeled MARKS) in binary liposomal system of phosphatidylcholine
and NBS-labeled phosphatidylserine, phase separation induced by the peptide was
reported [29]. Induction of hexagonal II structure and cubic structure was reported as
effects of diacylglycerol on physical property of lipid membranes [30]. From these
results, supposed mechanism of lipid second messenger inducing signaling process is
shown in Fig. 6.4. And lipid second messenger in signaling system of cell was
reviewed by Makowsky and O.M. Rosen [24]. On the other hand, Generation of
phosphatidic acids makes possible to translocate calcium ions through lipid membrane as shown in Fig. 6.5 [31].
6.5 Non-bilayer Forming Lipids and Function
of Biomembrane
Although basic structure of biomembrane is lipid bilayer membrane as assembly of
lipid molecules, the lipid membrane shows polymorphism in its structure and
physical property. Lipid molecule of cone shape prefers non-bilayer structure such
as hexagonal II and lipidic particle. And role of non-bilayer structure on function of
biomembrane was studied.
6.5.1 Membrane Structure Formed by Non-bilayer Forming
Lipids
Basic concept of biomembrane was established by ‘fluid mosaic membrane model’
proposed by Singer and Nicolson [32], but formation of non-bilayer structure under
a condition was observed by
31 P-NMR in 1978 [30], and then observed by freezefractured electron microscope [33]. From these results, relationship between
non-bilayer forming lipids and non-bilayer structure such as hexagonal II structure
6.5 Non-bilayer Forming Lipids and Function of Biomembrane
87