Diacylglycerol kinase ζ interacts with sphingomyelin synthase 1 and sphingomyelin synthase-related protein via different regions.

We previously reported that diacylglycerol (DG) kinase (DGK) δ interacts with DG-generating sphingomyelin synthase (SMS)-related protein (SMSr), but not SMS1 or SMS2, via their sterile α motif domains (SAMDs). However, it remains unclear whether other DGK isozymes interact with SMSs. Here, we found that DGKζ, which does not contain SAMD, interacts with SMSr and SMS1, but not SMS2.

Phosphatidylinositol 4,5-bisphosphate-specific phospholipase C β1 selectively binds dipalmitoyl and distearoyl phosphatidic acids via Lys946 and Lys951.

Phospholipase C (PLC) β1 hydrolyzes 1-stearoyl-2-arachidonoyl (18:0/20:4)-phosphatidylinositol (PtdIns) 4,5-bisphosphate to produce diacylglycerol, which is converted to phosphatidic acid (PtdOH), in the PtdIns cycle and plays pivotal roles in intracellular signal transduction. The present study identified PLCβ1 as a PtdOH-binding protein using PtdOH-containing liposomes. Moreover, the comparison of the binding of PLCβ1 to various PtdOH species, including 14:0/14:0-PtdOH, 16:0/16:0-PtdOH, 16:0/18:1-PtdOH, 18:0/18:1-PtdOH, 18:0/18:0-PtdOH, 18:1/18:1-PtdOH, 18:0/20:4-PtdOH, and 18:0/22:6-PtdOH, indicated that the interaction of PLCβ1 with 16:0/16:0-PtdOH was the strongest.

Relative intensities of prompt γ-rays from the 35Cl(n,γ)36Cl reaction with thermal neutrons as secondary γ-ray intensity standards.

The relative intensities of 16 prompt γ-rays from the (35)Cl(n,γ)(36)Cl reaction with a thermal neutron were precisely determined as secondary γ-ray intensity standards with HPGe detectors. The detection efficiencies were calibrated from 0.2 to 10.