Photosynthesis-dependent Ca2+ influx and functional diversity between phospholipases in the formation of cell polarity in migrating cells of red algae

Mammalian phospholipase D: Function, and therapeutics

Despite being discovered over 60 years ago, the precise role of phospholipase D (PLD) is still being elucidated. PLD enzymes catalyze the hydrolysis of the phosphodiester bond of glycerophospholipids producing phosphatidic acid and the free headgroup. PLD family members are found in organisms ranging from viruses, and bacteria to plants, and mammals. They display a range of substrate specificities, are regulated by a diverse range of molecules, and have been implicated in a broad range of cellular processes including receptor signaling, cytoskeletal regulation and membrane trafficking. Recent technological advances including: the development of PLD knockout mice, isoform-specific antibodies, and specific inhibitors are finally permitting a thorough analysis of the in vivo role of mammalian PLDs. These studies are facilitating increased recognition of PLD's role in disease states including cancers and Alzheimer's disease, offering potential as a target for therapeutic intervention.

Photosynthesis-dependent Ca2+ influx and functional diversity between phospholipases in the formation of cell polarity in migrating cells of red algae

Unicellular spore cells, designated as monospores (also called archeospores), are well known as migrating plant cells, in which establishment of the anterior-posterior axis directs asymmetrical distribution of F-actin. Since the mechanisms of cell polarity formation are not yet fully elucidated in monospores, we investigated the roles of phosphoinositide signaling systems and Ca2+ mobilization in migration. Although we have already found the critical involvement of phosphatidylinositol 3-kinase in the establishment of cell polarity, we recently demonstrated the important roles of extracellular Ca2+ influx, phospholipase C (PLC) and phospholipase D (PLD). The remarkable characteristics of these factors are that Ca2+ influx depends on photosynthetic activity and that PLC and PLD play roles in the establishment and maintenance of cell polarity, respectively. These findings could provide new insight into the regulation of migration in eukaryotic cells.