Bennett, M. B. | bioRxiv Science

bioRxiv2026

Anionic lipids regulate PLCβ membrane recruitment

Phospholipase C-{beta} (PLC{beta}) enzymes are essential effectors of G protein-coupled receptor signaling that hydrolyze phosphatidylinositol 4,5-bisphosphate (PIP2) at the plasma membrane to generate the second messengers inositol trisphosphate and diacylglycerol. PLC{beta}s play essential roles in diverse physiological processes, including cardiac and neuronal function, macrophage activation, and the pathogenesis of diseases such as hypertrophic cardiomyopathy. PLC{beta} enzymes are unique in that they are aqueous-soluble and must partition onto the membrane surface to access their substrate, making membrane association a critical regulatory step. For example, we recently demonstrated that G{beta}{gamma} activates PLC{beta} by membrane recruitment and orientation of the catalytic core on the membrane surface. Although PLC{beta} membrane recruitment is required for function, the molecular determinants governing this process remain incompletely understood. Using a quantitative membrane partitioning assay, we show that robust membrane association of PLC{beta} requires anionic phospholipids, whereas polar phospholipids cannot substitute. Membrane partitioning exhibits a steep dependence on anionic lipid abundance, which is mediated by electrostatic interactions between negatively charged lipids and basic residues within the distal C-terminal domain of PLC{beta}. We further demonstrate that anionic lipids cooperate with G{beta}{gamma} to regulate PLC{beta} membrane recruitment, such that the magnitude of G{beta}{gamma}-dependent recruitment is dictated by membrane anionic lipid content. These findings reconcile previous discrepancies regarding G{beta}{gamma}-mediated PLC{beta} membrane recruitment and establish membrane electrostatics as a key regulatory input that integrates lipid composition with G protein signaling to regulate PLC{beta} activity. SummaryMembrane association is a crucial component of PLC{beta} function and regulation, yet the mechanisms governing this process are poorly understood. The authors demonstrate that anionic lipids drive PLC{beta} membrane recruitment and influence G{beta}{gamma}-dependent activation, revealing how membrane composition shapes cellular signal transduction.

biophysics↗

bioRxiv2019

The geographic distribution of reef and oceanic manta rays in the south-east Indian and south-west Pacific Oceans

The reef manta ray, Mobula alfredi, occurs in tropical and warm temperate coastal waters, and around islands and reefs in the Pacific and Indian Oceans. Published records that relate to the distribution of M. alfredi in the south-east Indian and south-west Pacific Oceans are largely restricted to locations where there is a focus on manta ray ecotourism, with little information from elsewhere. Even less is known about the circumglobally distributed oceanic manta ray, Mobula birostris, for which there are few published sighting records. We collated n = 11,703 sighting records from Australian waters and offshore territories for M. alfredi sourced from scientific image databases (n = 10,715), aerial surveys (n = 375) and online reports (n = 613). From collated records, we confirm that the species shows an uninterrupted distribution within Australian coastal waters north of 26{degrees}S on the west coast to 31{degrees}S on the east coast, with a southernmost record at 34{degrees}S. Confirmed locations for M. birostris encompass a latitudinal range of 10-40{degrees}S. Records from more southerly locations relate to warm-water events. Sightings of M. birostris were rare, but were confirmed at several geographically separate locations, probably reflecting its preference for offshore waters. The study clarifies the occurrence and range of each species within coastal waters of the south-east Indian and south-west Pacific Oceans, and highlights regions in northern Australia that are of specific interest for future research into possible movements of individuals between international marine jurisdictions.

ecology↗