Multiple PIP2 dependent molecular processes including receptor activated phospholipase C activity occur at the neuronal plasma membranes, yet levels of this lipid at the plasma membrane are remarkably stable. Although the existence of unique pools of PIP2 supporting these events has been proposed, the mechanism by which they are generated is unclear. In Drosophila photoreceptors, the hydrolysis of PIP2 by G-protein coupled phospholipase C activity is essential for sensory transduction of photons. We identify dPIP5K as an enzyme essential for PIP2 re-synthesis in photoreceptors. Loss of dPIP5K causes profound defects in the electrical response to light and light-induced PIP2 dynamics at the photoreceptor membrane. Overexpression of dPIP5K was able to accelerate the rate of PIP2 synthesis following light induced PIP2 depletion. Other PIP2 dependent processes such as endocytosis and cytoskeletal function were unaffected in photoreceptors lacking dPIP5K function. These results provide evidence for the existence of a unique dPIP5K dependent pool of PIP2 required for normal Drosophila phototransduction. Our results define the existence of multiple pools of PIP2 in photoreceptors generated by distinct lipid kinases and supporting specific molecular processes at neuronal membranes.
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http://dx.doi.org/10.1371/journal.pgen.1004948 | DOI Listing |
Br J Pharmacol
January 2025
Department of Physiology and Pharmacology, School of Medicine, Tel Aviv University, Tel Aviv, Israel.
Background And Purpose: The antiepileptic drug ethosuximide (ETX) suppresses epileptiform activity in a mouse model of GNB1 syndrome, caused by mutations in Gβ protein, likely through the inhibition of G-protein gated K (GIRK) channels. Here, we investigated the mechanism of ETX inhibition (block) of different GIRKs.
Experimental Approach: We studied ETX inhibition of GIRK channels expressed in Xenopus oocytes with or without their physiological activator, the G protein subunit dimer Gβγ.
Neuron
January 2025
Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA. Electronic address:
Neurexin cell-adhesion molecules regulate synapse development and function by recruiting synaptic components. Here, we uncover a mechanism for presynaptic assembly that precedes neurexin recruitment, mediated by interactions between cytosolic proteins and membrane phospholipids. Developmental imaging in C.
View Article and Find Full Text PDFPhysiol Rev
January 2025
Department of Physiology and Membrane Biology, University of California, Davis, School of Medicine, Davis CA, 95616, USA.
Biology uses many signaling mechanisms. Among them, calcium and membrane potential are two prominent mediators for cellular signaling. TRPM4 and TRPM5, two calcium-activated monovalent cation-conducting ion channels, offer a direct linkage between these two signals.
View Article and Find Full Text PDFActa Neurobiol Exp (Wars)
January 2025
Laboratory of Animal Models, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
The phosphatase and tensin homolog deleted on chromosome 10 (PTEN) gene is a critical tumor suppressor that plays an essential role in the development and functionality of the central nervous system. Located on chromosome 10 in humans and chromosome 19 in mice, PTEN encodes a protein that regulates cellular processes such as division, proliferation, growth, and survival by antagonizing the PI3K‑Akt‑mTOR signaling pathway. In neurons, PTEN dephosphorylates phosphatidylinositol‑3,4,5‑trisphosphate (PIP3) to PIP2, thereby modulating key signaling cascades involved in neurogenesis, neuronal migration, and synaptic plasticity.
View Article and Find Full Text PDFMethods Mol Biol
January 2025
Departments of Neurology, and Anatomy and Cell Biology, Wayne State University School of Medicine, University Health Center, Detroit, MI, USA.
Molecular dynamics (MD) simulations enable in silico investigation of the dynamic behavior of proteins and protein complexes. Here, we describe MD simulations of the SNARE bundle forming the complex with the neuronal proteins Synaptotagmin-1 (Syt1) and Complexin (Cpx). Syt1 is the synaptic vesicle (SV) protein that serves as the neuronal calcium sensor and triggers synaptic fusion upon calcium binding, and this process is promoted and accelerated by Cpx.
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