Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2024.07.26.605271

Insight into the Interaction between Neuronal Calcium Sensors and Insulin

Peddapuvala, S. U. K.·Sharma, Y.·Sankeshi, V.
View original source ↗Export metadata ↓

Abstract

Calcium is crucial in insulin biology and Ca2+ sensor proteins enforced in insulin release and signalling. The neuronal calcium sensor proteins (NCS) such as NCS-1 and VILIP are shown to be involved in insulin secretion from {beta}-pancreatic cells. However, the expression of different NCS proteins in the pancreas and their functional significance and role in pathologies remained unexplored. The present work, through different biophysical methods, presented that NCS proteins interact with insulin. NCS-1, the founder member of NCS family proteins interacts with insulin in a Ca2+ independent manner and Ca2+ enhances the affinity of the interaction. The evolutionarily conserved cryptic EF-hand in NCS proteins was found to be an essential commodity for binding insulin. The presence of Ca2+ binding first EF-hand abolishes the interaction with insulin and suggests the significance of non-functional EF-hand. The fluorescence and circular dichroism (CD) spectroscopy show that insulin interaction induces structural changes in NCS-1, which is demonstrated by size exclusion chromatography and analytical ultra-centrifugation. The autism mutant NCS-1-R102Q relatively retained insulin binding properties but with a significant difference in binding thermodynamics. Considering substantial sequence similarity among different NCS proteins and localisation in the pancreas, we examined the insulin interaction with the neurocalcin delta (NCALD). The NCALD shows metal ion-independent insulin binding and contrary to NCS-1, the Ca2+ abolishes the insulin binding. This highlights the differential regulation of Ca2+ towards insulin interaction in NCS protein. Conclusively the present work highlight that NCS proteins interact with insulin and further investigation would aid to understand the significance of NCS proteins in insulin physiology/pathophysiology and possible new molecular targets in diabetes.

Explore related subjects

biophysicsPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Peddapuvala, S. U. K., Sharma, Y., Sankeshi, V.. 2024-07-26. Insight into the Interaction between Neuronal Calcium Sensors and Insulin. https://doi.org/10.1101/2024.07.26.605271

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Scaling of structural variability of ecDNA polymer condensates with copy number boosts and stabilises oncogene regulatory contacts

Extrachromosomal DNAs (ecDNAs) form highly heterogeneous condensates in cancer cells that drive oncogene overexpression, yet how structural variability coexists with stable gene regulation remains unclear. Here, we develop a minimal polymer physics model of MYC-harbouring COLO320-DM ecDNAs, where BRD4-like complexes bind and bridge cognate sites along ecDNA rings. Above a critical binder concentration, ecDNAs phase separate into condensates exhibiting diverse conformations because of their thermodynamic folding degeneracy. Despite this variability, condensates retain conserved interaction scaffolds that give rise to reproducible contact patterns, including in-trans associated domains (I-TADs), genomic regions enriched in intermolecular regulatory contacts between distinct ecDNAs. We find that condensate 3D architecture follows universal scaling relations with ecDNA copy number, n, remaining robust to model parameter changes. Regulatory contacts within I TADs increase linearly with n, yet they are one order of magnitude stronger than in size matched control regions outside I TADs, whereas their relative fluctuations are markedly suppressed as n increases. This scaling produces enhanced, low-noise regulatory environments for oncogenes embedded within I-TADs, such as PVT1-MYC fusions, whereas the canonical MYC copy, located outside, is less amplified as experimentally observed. Our findings reveal universal polymer physics principles underlying ecDNA condensate organization, offering a mechanistic basis for selective oncogene amplification and potential advantages in cancer progression.

biophysics↗
bioRxiv2026

High-resolution mapping of RNA structural maturation during Cas9 assembly with ABEL-FRET

The structural flexibility of RNA is essential for forming ribonucleoprotein (RNP) complexes, which regulate diverse biological processes. This intrinsic property permits RNA to act as a dynamic scaffold along the assembly pathway as it folds into a specific structure for initial recognition by protein and undergoes conformational rearrangements for functional maturation as a complex. Yet, RNA flexibility and RNP multicomponent assembly create significant obstacles for traditional structural methods. To overcome these challenges, we applied recently developed ABEL-FRET spectroscopy to measure tether-free single-molecule Forster resonance energy transfer (smFRET) over extended observation times. Furthermore, ABEL-FRET enables the unique ability for simultaneous measurements of ultrahigh resolution smFRET and hydrodynamic size of individual complexes, which offers distinct advantages for studying dynamic RNA molecules that undergo assembly via sequential binding events. Using ABEL-FRET, we explored how the guide RNA (gRNA) of CRISPR genome editing system folds and modulates its structural flexibility to carry out the roles required for each assembly state from its unbound apo form to the functional Cas9 RNP state for target DNA cleavage. Multi-perspective view of gRNA structure gained by probing its two primary functional domains enabled to capture dramatic changes in gRNA flexibility that are highly dependent on its specific structural domains as well as assembly states. Collectively, our work with ABEL-FRET highlights the intrinsic link between the structural flexibility of RNA and its functionality in RNP assembly.

biophysics↗
bioRxiv2026

De novo design of functional RNAs through higher-order interactions

Designing RNA sequences that reliably adopt functional three-dimensional structures remains a central challenge in RNA engineering because folding depends on cooperative interactions beyond canonical base pairing. Here we present DS3dRNA, an interaction-based framework for de novo RNA sequence design that combines a three-body statistical potential with physics-guided sequence sampling and supports design against multiple conformations. Across the evaluated benchmarks, DS3dRNA outperformed representative RNA inverse-design methods in native-sequence recovery and agreement between predicted and target structures. Energy-sequence-quality analyses further showed that lower design energies generally accompanied higher sequence recovery and macro-averaged F1 scores (MacroF1). Experimentally tested Mango II designs retained high-affinity fluorogenic activity, and five twister ribozyme designs yielded mean endpoint cleavage fractions of 37.7-50.6%, compared with 23.5% for the wild type. These results establish explicit higher-order interaction scoring as a complementary approach to emerging data-driven RNA design methods and provide a framework for designing functional RNAs from experimental or predicted structural ensembles.

biophysics↗