@article {120164, title = {Nanobody derived using a peptide epitope from the Spike protein receptor-binding motif inhibits entry of SARS-CoV-2 variants.}, journal = {J Biol Chem}, volume = {299}, year = {2023}, month = {2022 Nov 21}, pages = {102732}, abstract = {

The emergence of new escape mutants of the SARS-CoV-2 virus has escalated its penetration among the human population and has reinstated its status as a global pandemic. Therefore, developing effective antiviral therapy against emerging SARS-CoV variants and other viruses in a short period of time becomes essential. Blocking SARS-CoV-2 entry into human host cells by disrupting the Spike glycoprotein-angiotensin-converting enzyme 2 (ACE2) interaction has already been exploited for vaccine development and monoclonal antibody therapy. Unlike the previous reports, our study used a nine-amino acid peptide from the receptor-binding motif (RBM) of the Spike (S) protein as an epitope. We report the identification of an efficacious nanobody N1.2 that blocks the entry of pseudovirus-containing SARS-CoV-2 Spike as the surface glycoprotein. Moreover, using mCherry fluorescence based reporter assay we observe a more potent neutralizing effect against both the hCoV19 (Wuhan/WIV04/2019) and the Omicron (BA.1) pseudotyped Spike virus with a bivalent version of the N1.2 nanobody. In summary, our study presents a rapid, and efficient methodology to use peptide sequences from a protein-receptor interaction interface as epitopes for screening nanobodies against potential pathogenic targets. We propose that this approach can also be widely extended to target other viruses and pathogens in the future.

}, issn = {1083-351X}, doi = {10.1016/j.jbc.2022.102732}, author = {Mendon, Nivya and Ganie, Rayees and Kesarwani, Shubham and Dileep, Drisya and Sasi, Sarika and Lama, Prakash and Chandra, Anchal and Sirajuddin, Minhajuddin} } @article {84941, title = {Genetically encoded live-cell sensor for tyrosinated microtubules.}, journal = {J Cell Biol}, volume = {219}, year = {2020}, month = {2020 Oct 05}, abstract = {

Microtubule cytoskeleton exists in various biochemical forms in different cells due to tubulin posttranslational modifications (PTMs). Tubulin PTMs are known to affect microtubule stability, dynamics, and interaction with MAPs and motors in a specific manner, widely known as tubulin code hypothesis. At present, there exists no tool that can specifically mark tubulin PTMs in living cells, thus severely limiting our understanding of their dynamics and cellular functions. Using a yeast display library, we identified a binder against terminal tyrosine of α-tubulin, a unique PTM site. Extensive characterization validates the robustness and nonperturbing nature of our binder as tyrosination sensor, a live-cell tubulin nanobody specific towards tyrosinated microtubules. Using this sensor, we followed nocodazole-, colchicine-, and vincristine-induced depolymerization events of tyrosinated microtubules in real time and found each distinctly perturbs the microtubule polymer. Together, our work describes a novel tyrosination sensor and its potential applications to study the dynamics of microtubule and their PTM processes in living cells.

}, issn = {1540-8140}, doi = {10.1083/jcb.201912107}, author = {Kesarwani, Shubham and Lama, Prakash and Chandra, Anchal and Reddy, P Purushotam and Jijumon, A S and Bodakuntla, Satish and Rao, Balaji M and Janke, Carsten and Das, Ranabir and Sirajuddin, Minhajuddin} } @article {27663, title = {Female Density-Dependent Chemical Warfare Underlies Fitness Effects of Group Sex Ratio in Flour Beetles}, journal = {American Naturalist}, year = {2018}, month = {12/2017}, abstract = {

In animals, skewed sex ratios can affect individual fitness via sexual (e.g., intersexual conflict or intrasexual mate competition) or nonsexual (e.g., sex-specific resource competition) interactions. Because most analyses of sex ratio focus on sexual interactions, the relative importance of sexual versus nonsexual mechanisms remains unclear. We tested both mechanisms in the flour beetle Tribolium castaneum, where male-biased sex ratios increase female fitness relative to unbiased or female-biased groups. Although flour beetles show both sexual and nonsexual (resource) competition, we found that sexual interactions did not explain female fitness. Instead, female fecundity was dramatically reduced even after a brief exposure to flour conditioned by other females. Earlier studies suggested that secreted toxins might mediate density-dependent population growth in flour beetles. We identified ethyl benzoquinone and methyl benzoquinone (quinones) as components of adult stink glands that regulate female fecundity. In female-biased groups (i.e., at high female density), females upregulated quinones and suppressed each other{\textquoteright}s reproduction. In male-biased groups, low female density and associated low quinone levels maximized fecundity. Thus, females appear to use quinones as weapons for female-specific, density-dependent interference competition. Our results underscore the importance of nonsexual interference competition that may often underlie the fitness consequences of skewed sex ratios.

}, doi = {10.1086/695806}, author = {Khan, Imroze and Prakash, Arun and Issar, Swastika and Umarani, Mihir and Sasidharan, Rohit and Masagalli, JN and Lama, Prakash and Venkatesan, Radhika and Agashe, Deepa} }