@article {47986, title = {Molecular mechanisms underlying caveolin-1 mediated membrane curvature}, journal = {Journal of Membrane Biology}, volume = {255}, year = {2022}, month = {JUN}, pages = {225-236}, type = {Article}, abstract = {

Caveolin-1 is one of the main protein components of caveolae that acts as a mechanosensor at the cell membrane. The interactions of caveolin-1 with membranes have been shown to lead to complex effects such as curvature and the clustering of specific lipids. Here, we review the emerging concepts on the molecular interactions of caveolin-1, with a focus on insights from coarse-grain molecular dynamics simulations. Consensus structural models of caveolin-1 report a helix-turn-helix core motif with flanking domains of higher disorder that could be membrane composition dependent. Caveolin-1 appears to be mainly surface-bound and does not embed very deep in the membrane to which it is bound. The most interesting aspect of caveolin-1 membrane binding is the interplay of cholesterol clustering and membrane curvature. Although cholesterol has been reported to cluster in the vicinity of caveolin-1 by several approaches, simulations show that the clustering is maximal in membrane leaflet opposing the surface-bound caveolin-1. The intrinsic negative curvature of cholesterol appears to stabilize the negative curvature in the opposing leaflet. In fact, the simulations show that blocking cholesterol clustering (through artificial position restraints) blocks membrane curvature, and vice versa. Concomitant with cholesterol clustering is sphingomyelin clustering, again in the opposing leaflet, but in a concentration-dependent manner. The differential stress due to caveolin-1 binding and the inherent asymmetry of the membrane leaflets could be the determinant for membrane curvature and needs to be further probed. The review is an important step to reconcile the molecular level details emerging from simulations with the mesoscopic details provided by state of the art experimental approaches. [GRAPHICS] .

}, keywords = {Cholesterol clustering, Membrane curvature, Protein-lipid interactions}, issn = {0022-2631}, doi = {10.1007/s00232-022-00236-y}, author = {Prakash, Shikha and Malshikare, Hrushikesh and Sengupta, Durba} } @article {48736, title = {Differential membrane curvature induced by distinct protein conformers}, journal = {Soft Matter}, volume = {19}, year = {2023}, month = {JUN }, pages = {4021-4028}, type = {Article}, abstract = {

Membrane topology changes are associated with various cellular processes and are modulated by synergistic effects between lipid composition and membrane-associated proteins. However, how protein shape or conformational dynamics couples to membrane molecular properties remains unclear. In this work, we aim to investigate this coupling behavior using the curvature-inducing protein caveolin-1. We considered distinct protein conformers of the helical hairpin protein corresponding to different protein shapes, such as the wedge and the banana-shaped conformers. The different protein conformers were simulated in a coarse-grain representation in the presence of cholesterol-sphingomyelin rich membrane. We observed that membrane curvature is dependent on protein shape and is the lowest for the wedge conformer and maximal for the banana conformer. The differences in the net stress between the two membrane leaflets, calculated from the lateral pressure profile distributions in lipid bilayers for different protein conformers, show a similar trend. In conjunction, we show that cholesterol and sphingomyelin clustering in the membrane is modulated by protein shape. Overall, our results provide molecular-level insights into the coupling between membrane topology, protein shape and lipid clustering in cell membranes.

}, issn = {1744-683X}, doi = {10.1039/d3sm00218g}, author = {Malshikare, Hrushikesh and Prakash, Shikha and Sengupta, Durba} } @article {49808, title = {Membrane remodeling by the caveolin-1 8s oligomeric complex}, journal = {Biophysical Journal}, volume = {124}, year = {2025}, month = {OCT}, pages = {3206-3216}, type = {Article}, abstract = {

Caveolin-1 is a scaffolding protein crucial for the formation of caveolae, specialized membrane structures that are involved in diverse cellular processes such as endocytosis, mechanosensing, and lipid regulation. Recently, a unique structure of the 8S oligomeric complex of caveolin-1 was resolved by cryoelectron microscopy, providing a foundational basis for understanding its molecular mechanisms. In this study, we probe the membrane interactions of the oligomeric caveolin-1 complex in membrane lipid bilayers and vesicles. We performed coarse-grained molecular dynamics simulations to delineate the interactions of the palmitoylated and nonpalmitoylated caveolin-1 with multicomponent membranes. During the simulations, the caveolin-1 complex binds to the membranes, partially to one of the leaflets in a shallow monotopic arrangement. A remodeling of the lipids in its vicinity of the complex was observed in both vesicles and planar bilayers. However, the caveolin-1 complex binds to vesicles without inducing any significant change to the curvature, whereas it appears to induce increased curvature in the planar bilayers leading to the formation of highly curved nanodomains. Cholesterol and phosphoserine lipid enrichment, hallmarks of caveolin-1 binding, were observed in a membrane topology-dependent manner. The differential cholesterol clustering observed between vesicles and bilayers highlights the curvature-dependent nature of caveolin-1-mediated lipid organization. Our work highlights the dual significance of lipid organization and membrane topology in the functional dynamics of caveolin-1, shedding light on its role in inducing and sensing membrane curvature, which is pivotal for various cellular processes. SIGNIFICANCE The rather unanticipated experimental structure of the oligomeric complex of caveolin-1 has opened up multiple questions such as how caveolin-1 interacts with cell membranes and how curvature can be induced or stabilized by a relatively flat protein complex. Here, we identify the molecular mechanisms underlying membrane curvature by caveolin-1 using coarse-grained molecular dynamics simulations. We show that the caveolin-1 complex can bind in a shallow monotopic arrangement and initiate clustering cholesterol and phosphoserine lipids. In vesicles, caveolin-1 binding does not lead to differences in curvature, but binding to planar bilayer leads to the formation of highly curved nanodomains. Our work is an important step to identify novel mechanisms of caveolin-1 stabilized or induced membrane curvature.

}, issn = {0006-3495}, doi = {10.1016/j.bpj.2025.08.019}, author = {Malshikare, Hrushikesh and Sengupta, Durba} } @article {50039, title = {Mechanistic principles of antimicrobial peptides uncovered by charge density-based machine learning}, journal = {Chemical Communications}, volume = {62}, year = {2026}, month = {FEB}, pages = {PMID 9610838}, type = {Article}, abstract = {

Antimicrobial peptides (AMPs) are emerging as potent alternatives to conventional antibiotics, yet their diverse nature due to divergent mechanisms of action hinders rational design. Here, we present an electrostatics-stratified computational framework that uncovers key physicochemical principles governing AMP activity. Experimentally validated peptides were grouped by average charge per residue (i.e., the charge/length of the peptide) and analyzed through integrated sequence-, structure-, and chemistry-based descriptors. Distinct molecular signatures emerged across electrostatic regimes: low-charge/length peptides rely on amphipathic organization via structural compactness, whereas the intermediate-charge/length peptides exhibit balanced hydrophobicity and electrostatics. The high-charge peptides couple strong cationic attraction with lipophilicity and tryptophan anchoring to mainly disrupt membranes. Interestingly, hydrophobic moment, which is a measure of the amphipathicity, is found to be important in all three classes of AMPs. This study identifies distinguishing features of AMP sub-groups and suggests design guidelines for developing selective and potent next-generation AMPs.

}, issn = {1359-7345}, doi = {10.1039/d5cc06374d}, author = {Malshikare, Hrushikesh and Priyakumar, U. Deva and Chatterjee, Prathit and Sengupta, Durba} }