Fumio Yoshikawa

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In a variety of cells, the Ca2+ signalling process is mediated by the endoplasmic-reticulum-membrane-associated Ca2+ release channel, inositol 1,4,5-trisphosphate (InsP3) receptor (InsP3R). Being ubiquitous and present in organisms ranging from humans to Caenorhabditis elegans, InsP3R has a vital role in the control of cellular and physiological processes(More)
Human bone marrow-derived mesenchymal stem cells (hMSCs) have the potential to differentiate into several types of cells. Calcium ions (Ca(2+)) play an important role in the differentiation and proliferation of hMSCs. We have demonstrated that spontaneous [Ca(2+)](i) oscillations occur without agonist stimulation in hMSCs. However, the precise mechanism of(More)
The release of calcium ions (Ca(2+)) from their intracellular stores is essential for the fertilization of oocytes of various species. The calcium pools can be induced to release Ca(2+) via two main types of calcium channel receptor: the inositol 1,4,5-trisphosphate receptor (IP(3)R) and the ryanodine receptor. Starfish oocytes have often been used to study(More)
BACKGROUND Phospholipase D (PLD) catalyzes conversion of phosphatidylcholine into choline and phosphatidic acid, leading to a variety of intracellular signal transduction events. Two classical PLDs, PLD1 and PLD2, contain phosphatidylinositide-binding PX and PH domains and two conserved His-x-Lys-(x)(4)-Asp (HKD) motifs, which are critical for PLD activity.(More)
Opalin is a transmembrane protein detected specifically in mammalian oligodendrocytes. Opalin homologs are found only in mammals and not in the genome sequences of other animal classes. We first determined the nucleotide sequences of Opalin orthologs and their flanking regions derived from four prosimians, a group of primitive primates. A global comparison(More)
In contrast to compact myelin, the series of paranodal loops located in the outermost lateral region of myelin is non-compact; the intracellular space is filled by a continuous channel of cytoplasm, the extracellular surfaces between neighboring loops keep a definite distance, but the loop membranes have junctional specializations. Although the proteins(More)
The cerebellar cortical circuit of mammals develops via a series of magnificent cellular events in the postnatal stage of development to accomplish the formation of functional circuit architectures. The contribution of genetic factors is thought to be crucial to cerebellar development. Therefore, it is essential to analyze the underlying transcriptome(More)
Mouse embryonic stem (mES) cells have the potential to differentiate into all types of cells, but the physiological properties of undifferentiated mES cells, including Ca2+ signaling systems, are not fully understood. In this study, we investigated Ca2+ signaling pathways in mES cells by using confocal Ca2+ imaging systems, patch clamp techniques and(More)
We have developed a novel recombinant hyperaffinity inositol 1,4,5-trisphosphate (IP(3)) absorbent, called the "IP(3) sponge," which we constructed on the basis of the ligand-binding site of the mouse type 1 IP(3) receptor (IP(3)R1). The IP(3) sponge exhibited approximately 1000-fold higher affinity for IP(3) than the parental IP(3)R1 and specifically(More)