Phosphatidylinositol-5-phosphate (PI-5-P) is a newly identified phosphoinositide with characteristics of a signaling lipid but no known cellular function. PI-5-P levels are controlled by the type II PI-5-P 4-kinases (PIP4K IIs), a family of kinases that converts PI-5-P into phosphatidylinositol-4,5-bisphosphate (PI-4,5-P2). The PI-5-P pathway is an alternative route for PI-4,5-P2 synthesis as t...

Although PI(4,5)P2 is believed to play an essential role in regulating the activity of numerous ion channels and transporters, the mechanisms by which it does so are unknown. Here, we used the ability of the TRPV1 ion channel to discriminate between PI(4,5)P2 and PI(4)P to localize the region of TRPV1 sequence that interacts directly with the phosphoinositide. We identified a point mutation in ...

About 10 years ago there was a heated debate over whether v-Src and several other retrovirally encoded protein-tyrosine kinases had lipid kinase activity in addition to protein kinase activity. Ultimately, the analysis of the unusual lipid kinase activity associated with v-Src led to the discovery of a novel type of phosphatidylinositol (PI) kinase, the PI 3-kinases. This in turn led to the cha...

The opportunistic intracellular pathogen Legionella pneumophila is the causative agent of Legionnaires' disease. L. pneumophila delivers nearly 300 effector proteins into host cells for the establishment of a replication-permissive compartment known as the Legionella-containing vacuole (LCV). SidC and its paralog SdcA are two effectors that have been shown to anchor on the LCV via binding to ph...

For integers $$0 < r \le t$$ , let the function $$D_{r,t}(n)$$ denote number of parts among all partitions n into distinct that are congruent to modulo t. We prove asymptotic formula $$\begin{aligned} D_{r,t}(n) \sim \dfrac{3^{\frac{1}{4}} e^{\pi \sqrt{\frac{n}{3}}}}{2\pi t n^{\frac{1}{4}}} \left( \log (2) + \dfrac{\sqrt{3} (2)}{8\pi } - \dfrac{\pi }{4\sqrt{3}} \dfrac{t}{2} \right) n^{- \frac{1...

Activation of macrophages with stimuli of the innate immune response results in the intense remodeling of arachidonate-containing phospholipids, leading to the mobilization of large quantities of this fatty acid for conversion into biologically active eicosanoids. As a consequence of this process, the arachidonate levels in membrane phospholipids markedly decrease. We have applied mass spectrom...

Downregulation of cell-cell adhesion and upregulation of cell migration play critical roles in the conversion of benign tumors to aggressive invasive cancers. In this study, we show that changes in cell-cell adhesion and cancer cell migration/invasion capacity depend on the level of phosphatidylinositol 4-phosphate [PI(4)P] in the Golgi apparatus in breast cancer cells. Attenuating SAC1, a PI(4...

A close correlation between Stiles's increment threshold (pi-mechanism) approach and color discrimination at threshold was found: a sharp transition from detection of two lights via two pi-mechanisms (pi 1 and pi 4) to detection via only one pi-mechanism (pi 1) was paralleled by a sharp decline from excellent discrimination between those two lights (even with the rods bleached) to no discrimina...

In this work, a polyimide (PI) containing triazole units was synthesized using 3,5-diamino-1,2,4-triazole and pyromellitic dianhydride in N-methyl-2-pyrrolidinone. This polymer was used as the support of manganese (III) tetrakis(4-methoxylphenyl)porphyrin acetate to attain a heterogeneous catalyst; namely Mn(T4-OMePP)OAc@PI. The synthesized PI and Mn(T4-OMePP)OAc@PI were characterized by di...

The regulation of autophagy-dependent lysosome homeostasis in vivo is unclear. We showed that the inositol polyphosphate 5-phosphatase INPP5K regulates autophagic reformation (ALR), a recycling pathway, muscle. hydrolyzes phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2] to phosphatidylinositol 4-phosphate [PI(4)P], and mutations cause muscular dystrophy by unknown mechanisms. report loss muscl...