Photolysis of cell-permeant caged inositol pyrophosphates controls oscillations of cytosolic calcium in a β-cell line

Abstract

β-Cells respond directly to the intracellular photochemical release of caged inositol pyrophosphate isomers with modulations of oscillations in cytosolic Ca2+.

Inositol polyphosphates promote T cell-independent humoral immunity via the regulation of Bruton’s tyrosine kinase

“…To confirm that BCR signaling requires higher order InsPs, we tested if cell permeable InsP could rescue the impairment in activation of IPMK-deficient B cells. Fo B cells and MZ B cells isolated from IPMK cKO mice were activated in the presence of cell permeable InsP 5 or InsP 6 (39)(40)(41), and then the phosphorylation of Btk and PLCγ2 was measured. The treatment with cell permeable InsP 6 only resulted in substantial restoration of phosphorylation of both Btk and PLCγ2 after stimulation with anti-IgM ( Fig.…”

The inositol pyrophosphate 5-InsP 7 drives sodium-potassium pump degradation by relieving an autoinhibitory domain of PI3K p85α

“…To obtain direct evidence that 5-InsP 7 mediates Na + /K + -ATPase-1 endocytosis, we overexpressed green fluorescent protein (GFP)-fused Na + /K + -ATPase-1 in HEK 293 cells, and treated the cells with cell-permeant photocaged 5-InsP 7 ( fig. S6C) (22) to observe its influence upon GFP-fused Na + /K + -ATPase-1 in real time via confocal microscopy ( Fig. 3G).…”

Metabolism and Functions of Inositol Pyrophosphates: Insights Gained from the Application of Synthetic Analogues

“…The resultant, uncharged molecule can penetrate the plasma membrane, and once it is inside cells, intracellular esterases cleave the masking groups and yielded the native inositol phosphate. This technique has been adapted by Jessen and colleagues [ 69 ], such that caged 5-InsP 7 was made cell-permeable by attaching acetoxybenzyl groups to the monophosphates and DEACM was added to the 5-β-phosphate ( Figure 4 B). Cell loading and removal of the acetoxybenzyl moieties was completed within 4 hr.…”