Biology subjects

Wise, M.

Publications and source records attributed to Wise, M..

3 recordsLinked to original sources

bioRxiv2026

Two Pleckstrin homology domains scaffold SNAP-47-containing SNARE complexes

Long-term potentiation requires the regulated insertion of AMPA receptors into the postsynaptic membrane of neurons, a process mediated by a SNARE complex containing SNAP-47, syntaxin-3, and synaptobrevin-2. Compared to other SNAP proteins, SNAP-47 exhibits slower fusion kinetics and contains uncharacterized regions whose functions remain unclear. Here, we integrated biochemical approaches with artificial intelligence structure prediction tools and molecular dynamics to investigate the architecture of SNAP-47-containing SNARE complexes. AlphaFold3 predictions of the ternary SNAP-47-containing SNARE complex revealed one known Pleckstrin homology domain (PH1) and one previously unidentified PH domain (PH2), which we validated experimentally. BioEmu and molecular dynamics simulations indicated that PH1 and PH2 form a stable and energetically favorable interface. In this bound state, PH1 stably interacted with the SNARE coiled coil, and in silico acetylation at a lysine whose acetylation is known to impair SNAP-47 function disrupted this PH1-SNARE interface. AMPAR insertion via SNAP-47-containing SNARE complexes is triggered by the calcium sensor synaptotagmin, and we observed that PH1, PH2, and synaptotagmin-1 can simultaneously engage with the plasma membrane, consistent with a pro-fusion conformation. Together, we provide new mechanistic insight into how PH domains regulate SNAP-47-mediated membrane fusion during synaptic plasticity.

molecular biology↗

bioRxiv2024

Multiple pathways for licensing human replication origins

The loading of replicative helicases constitutes an obligatory step in the assembly of DNA replication machineries. In eukaryotes, the MCM2-7 replicative helicase motor is deposited onto DNA by the origin recognition complex (ORC) and co-loader proteins as a head-to-head MCM double hexamer to license replication origins. Although extensively studied in the budding yeast model system, the mechanisms of origin licensing in higher eukaryotes remain poorly defined. Here, we use biochemical reconstitution and electron microscopy (EM) to reconstruct the human MCM loading pathway. Unexpectedly, we find that, unlike in yeast, ORCs Orc6 subunit is not essential for human MCM loading but can enhance loading efficiency. EM analyses identify several intermediates en route to MCM double hexamer formation in the presence and absence of Orc6, including an abundant DNA-loaded, closed-ring single MCM hexamer intermediate that can mature into a head-to-head double hexamer through different pathways. In an Orc6-facilitated pathway, ORC and a second MCM2-7 hexamer are recruited to the dimerization interface of the first hexamer through an MCM-ORC intermediate that is architecturally distinct from an analogous intermediate in yeast. In an alternative, Orc6-independent pathway, MCM double hexamer formation proceeds through dimerization of two independently loaded single MCM2-7 hexamers, promoted by a propensity of human MCM2-7 hexamers to dimerize without the help of other loading factors. This redundancy in human MCM loading pathways likely provides resilience against replication stress under cellular conditions by ensuring that enough origins are licensed for efficient DNA replication. Additionally, the biochemical reconstitution of human origin licensing paves the way to address many outstanding questions regarding DNA replication initiation and replication-coupled events in higher eukaryotes in the future.

biochemistry↗

bioRxiv2019

Bacterial Glycogen as a Durable Energy Reserve Contributing to Persistence: An Updated Bibliography and Mathematical Model

Glycogen is conventionally viewed as a transient energy reserve that can be rapidly synthesized for glucose accumulation or mobilized for ATP production and blood glucose homeostasis in higher organisms. However, this understanding is not completely applicable to prokaryotes due to glycogen structural heterogeneity. A number of studies have noted that glycogen with short average chain length gc in bacteria has the potential to degrade slowly, which might prolong bacterial survival in the environment and thus enhance potential for transmission to new hosts. This phenomenon has been examined over the past few years and called the durable energy storage mechanism hypothesis (DESM). In this updated bibliography, we summarize recent progress and provide a mathematical model of glycogen as a durable energy reserve.

microbiology↗