Biology subjects

Golovin, A. V.

Publications and source records attributed to Golovin, A. V..

4 recordsLinked to original sources

bioRxiv2025

Every Piece of the Puzzle Matters: A Novel Zinc-Binding Site in the Luminal Domain of STIM1 Drives Clustering

STIM1 is pivotal in the tightly regulated mechanism controlling calcium homeostasis in the ER. It is activated by calcium dissociation from its EF-hand domain when ER calcium levels decrease, leading to its interaction with the ORAI channel to initiate calcium influx. Despite advancements in understanding the complex STIM1 machinery, including its domain organization and structural rearrangements upon activation, many aspects of this process remain poorly understood. In this study, we focused on a small conserved region situated upstream to the EF-hand, which has been previously shown to be involved in the modulation of STIM1 by ROS. Our findings reveal that this region binds zinc and plays a pivotal role in STIM1 activation by promoting its clustering, a process essential for the activation of calcium influx. These results revealed the functional importance of this domain and added a crucial piece to the puzzle of how calcium and zinc signaling are interconnected. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=110 SRC="FIGDIR/small/659323v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@16efeborg.highwire.dtl.DTLVardef@1e15e96org.highwire.dtl.DTLVardef@108cad0org.highwire.dtl.DTLVardef@3b58b0_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2024

A new nanoDSF approach to anti-tubulin compounds screening revealed novel MTAs among approved drugs.

Microtubule Targeting Agents (MTAs) constitute a vital category of tubulin-binding compounds, deployed across anticancer therapies. Despite the array of MTA drugs developed by pharmaceutical entities, the quest for novel efficacious molecules continues unabated. We unveil an innovative in vitro MTA screening methodology employing nano differential scanning fluorimetry (nanoDSF), presenting distinct advantages over known assays. This novel approach not only assesses compound-tubulin binding but also quantitatively analyzes their impact on tubulin polymerization. Proposed nanoDSF assay was rigorously validated using the Prestwick Chemical Library, which encompasses 1,520 approved compounds, successfully identifying all previously known MTAs. Furthermore, this screening has unearthed potential anti-tubulin agents among drugs currently utilized for non-related medical conditions, offering insights into their mechanisms of action in inhibiting cancer cell proliferation and/or inducing cytotoxicity. These discoveries herald new opportunities for drug repositioning involving the newly identified MTAs and substantially streamline the process of screening extensive chemical libraries for MTAs featuring novel chemical structures.

cancer biology↗

bioRxiv2021

Sequential binding of zinc triggers tau aggregation

Tau protein has been extensively studied due to its key roles in microtubular cytoskeleton regulation and in the formation of aggregates found in some neurodegenerative diseases. Recently it has been shown that zinc is able to induce tau aggregation by interacting with several binding sites. However, the precise location of these sites and the molecular mechanism of zinc-induced aggregation remain unknown. Here we used Nuclear Magnetic Resonance (NMR) to identify zinc binding sites on hTau40 isoform. These experiments revealed three distinct zinc binding sites on tau, located in the N-terminal part (H14, H32, H94, and H121), the repeat region (H299, C322, H329 and H330) and the C-terminal part (H362, H374, H388 and H407). Further analysis enabled us to show that the C-terminal and the N-terminal sites are independent of each other. Using molecular simulations, we modeled the structure of each site in a complex with zinc. Given the clinical importance of zinc in tau aggregation, our findings pave the way for designing potential therapies for tauopathies. HighlightsO_LIZinc is known to induce tau aggregation in neurodegenerative diseases C_LIO_LIZinc binding locations and mechanism are not yet clear C_LIO_LIUsing NMR we localized 3 zinc binding site on tau C_LIO_LIBy molecular simulations, we proposed a modeled structure of each site C_LIO_LIOur findings pave the way for designing potential therapies for tauopathies C_LI

molecular biology↗

bioRxiv2021

Mechanisms and evolutionary implications of integration of different functions within HIV-1 Tat

During evolution, viruses had to adapt to an increasingly complex environment of eukaryotic cells. Viral proteins that need to enter the cell nucleus or associate with nucleoli possess nuclear localization signals (NLSs) and nucleolar localization signals (NoLSs) for nuclear and nucleolar accumulation, respectively. As viral proteins are relatively small, acquisition of novel sequences seems to be a more complicated task for viruses than for eukaryotes. Here, we carried out a comprehensive analysis of the basic domain (BD) of HIV-1 Tat to show how viral proteins might evolve with NLSs and NoLSs without an increase in protein size. The HIV-1 Tat BD is involved in several functions, the most important being the transactivation of viral transcription. The BD also functions as an NLS, although it is substantially longer than a typical NLS. It seems that different regions in the BD could function as NLSs due to its enrichment with positively charged amino acids. Additionally, the high positive net charge inevitably causes the BD to function as an NoLS through a charge-specific mechanism. The integration of NLSs and NoLSs into functional domains enriched with positively charged amino acids might be a mechanism that allows the condensation of different functional sequences in small protein regions and, as a result, to reduce protein size, influencing the origin and evolution of NLSs and NoLSs in viruses.

evolutionary biology↗