Golgi screen identifies the RhoGEF Solo as a novel regulator of RhoB and endocytic transport
C. Lungu, F. Meyer, M. Hörning, J. Steudle, A. Braun, B. Noll, D. Benz, F. Fränkle, S. Schmid, S.A. Eisler and M.A. OlayioyeTraffic
, 1-15, 2023
- doi : 10.1111/tra.12880
Brief Summary: ''... Here, a microscopy-based RNAi screen was performed, and the RhoGEF protein Solo was identified as a functional counterplayer of DLC3, a RhoGAP protein with established roles in membrane trafficking. Biochemical, imaging and optogenetics assays further uncover Solo as a novel regulator of endosomal RhoB. Solo and DLC3 was found to control not only the activity, but also total protein levels of RhoB in an antagonistic manner. Together, the results of the study uncover the first functionally connected RhoGAP-RhoGEF pair at endomembranes, placing Solo and DLC3 at the core of endocytic trafficking.''
Optimization of Mechanosensitive Cross-talk between Matrix Stiffness and Protein Density: Independent Matrix Properties Regulate Spreading Dynamics of Myocytes
J. Brock, J. Erhardt, S.A. Eisler, and M. HörningCells
, 11, 2122, 2022
- doi : 10.3390/cells11132122
Brief Summary: ''... Here, C2C12 myocytes were monitored on L-DOPA functionalized hydrogels of 22 different elasticity and fibronectin density compositions. We observed a fibronectin density independent increase of the projected cell area until 12 kPa and an optimal fibronectin density at about 2.6 μg/cm2 with a maximum actin filament to cell area ratio of 7.5%. The proliferation evaluation of cells showed an opposite correlation between cell spreading duration and speed to the matrix elasticity and protein density, which did not affect the cell cycle duration.''
Galvanotaxis of ciliates: Spatiotemporal dynamics of Coleps hirtus under electric fields
A. Daul, M.-L. Lemloh, and M. HörningNew Journal of Physics
, 24, 053040,
- doi : 10.1088/1367-2630/ac6c47
Brief Summary: ''... Here, we statistically analyze the galvanotactic dynamics of C. hirtus by automated cell tracking routines. We found that the number of cells that show a galvanotactic response, increases with the increase of the applied electric field strength. The spatiotemporal swimming dynamics change and lead to a statistical increase of linear elongated cell trajectories that point toward the cathode. Further, the increase of the electric fields decreases the mean velocity variance, while showing no significant change in the absolute velocity for any applied electric field.''
Correlation of mitochondrial TOM core complex stop-and-go and open-closed
S. Wang, L. Findeisen, S. Leptihn, M.I. Wallace, M. Hörning and S. NussbergerCommunications Biology
, 5, 471, 2022
- doi : 10.1038/s42003-022-03419-4
Brief Summary: ''... Here we show the correlation between lateral protein diffusion and channel activity of the general protein import pore of mitochondria (TOM-CC) in membranes resting on ultrathin hydrogel films. We find that TOM-CC switches reversibly between three states of ion permeability associated with protein diffusion. We explain this behavior by the mechanical interaction between the hydrogel and the two β-barrel pores of TOM-CC.''
Optical Ultrastructure of Large Mammalian Hearts recovers Discordant Alternans by in-silco Data Assimilation
A. Loppini, J. Erhardt, F. H. Fenton, S. Filippi, M. Hörning and A. Gizzi Frontiers in Network Physiology
, 2, 866101, 2022
doi : 10.3389/fnetp.2022.866101
Brief Summary: ''... Here we apply Fourier transformation imaging (FFI) to whole-ventricle fluorescence observations, and identified complex spatial patterns of voltage alternans to characterize higher-order rhythms. By integration of the optical ultrastructure obtained by the FFI analysis a fine-tuned electrophysiological mathematical model of the cardiac action potential is implemented to reproduce complex alternans patterns in two-dimensional computational domains.''
Local membrane curvature pins and guides excitable membrane waves in chemotactic and macropinocytic cells - biomedical insights from an innovative simple model
M. Hörning, T. Bullmann and T. ShibataFrontiers in Cell and Developmental Biology
, 9, 2467, 2021
doi : 10.3389/fcell.2021.670943
Brief Summary: ''... Here, using 3D spatial fluctuation and phase map analysis on actin polymerization inhibited Dictyostelium cells, we reveal a spatial asymmetry of PIP3 signaling on the membrane that is mediated by the contact perimeter of the plasma membrane. We show that the contact perimeter guides PIP3 waves and acts as a pinning site of PIP3 phase singularities. The contact perimeter serves as a diffusion influencing boundary that is regulated by a cell size- and shape-dependent curvature.''
Precision 3D-printed cell scaffolds mimicking native tissue composition and mechanics
A. Erben, M. Hörning, B. Hartmann, T. Becke, S.A. Eisler, A. Southan, S. Cranz, O. Hayden, N. Kneidinger, M. Königshoff, M. Lindner, G.E.M. Tovar, G. Burgstaller, H. Clausen-Schaumann, S. Sudhop and M. HeymannAdvanced Healthcare Materials
, 200918, 2020
doi : 10.1002/adhm.202000918
Brief Summary: ''... Here, two‐photon stereolithography is adopted to print up to mm‐sized high‐precision 3D cell scaffolds at micrometer resolution with defined mechanical properties from protein‐based resins... with varying Young's moduli ranging from 7‐300 kPa are printed. This approach will allow for a systematic investigation of single‐cell and tissue dynamics.''
Circulating re-entrant waves promote maturation of hiPSC-derived cardiomyocytes in self-organized tissue ring
J. Li, L. Zhang, L. Yu, I. Minami, S. Miyagawa, M. Hörning, J. Dong, J. Qiao, X. Qu, Y. Hua, Fujimoto, Y. Shiba, Y. Zhao, F. Tang, S. Miyagawa, Y. Chen, Y. Sawa, C. Tang, L. LiuComunications Biology
, 3, 122, 2020
doi : 10.1038/s42003-020-0853-0
Brief Summary: ''HiPSC-derived cardiomyocytes can form three-dimensional self-organized tissue rings... the trained tissue show matured features including increased cardiac-specific gene expression, enhanced Ca2+-handling properties, an increased oxygen-consumption rate, and enhanced contractile force. A mathematical model interprets the origination, propagation, and long-term behavior of the findings.''
Mineralized scale patterns on the cell periphery of the chrysophyte Mallomonas determined by comparative 3D Cryo-FIB SEM data processing
M. Hörning, A. Schertel, R. Schneider, M.-L. Lemloh, M. R. Schweikert, and I. M. WeissJournal for Structural Biology
, 209, 107403, 2020
doi : 10.1016/j.jsb.2019.10.005
Brief Summary: ''Computational automated routines and principal component analysis of the experimentally extracted Mallomonas data created a realistic mathematical model based on the Fibonacci pattern theory. A complete in silico scale case of Mallomonas was reconstructed showing an optimized scale coverage on the cell surface.''
Three-dimensional cell geometry controls excitable membrane signaling in Dictyostelium cells
M. Hörning and T. ShibataBiophysical Journal
116(2), 372-382, 2019
doi : 10.1016/j.bpj.2018.12.012
Brief Summary: ''Using a novel method of three-dimensional analysis of the entire cell membrane of Dictyostelium cells, we found that PtdInsP3 domains can propagate persistently in any direction on the entire plasma membrane, while their propagation direction and speed are governed by the geometry of the cell.''
Dynamics of spatiotemporal line defects and chaos control in complex excitable systems
M. Hörning, F. Blanchard, A. Isomura and K. Yoshikawa
Scientific Reports, 7, 7757, 2017
- doi : 10.1038/s41598-017-08011-z
Brief Summary: ''The spatiotemporal dynamics of line defects in rotating spiral waves is observed. Combining a novel signaling over-sampling technique with multi-dimensional Fourier analysis shows that line defects can translate, merge, collapse and form stable singularities with even and odd parity while maintaining a stable oscillation of the spiral wave in the tissue.''
Dynamic Mechano-Regulation of Myoblast Cells on Supramolecular Hydrogels Cross-Linked by Reversible Host-Guest Interactions
M. Hörning§, M. Nakahata§, P. Linke, A. Yamamoto, M. Veschgini, S. Kaufmann, Y. Takashima, A. Harada and M. Tanaka
Scientific Reports, 7, 7760, 2017
- doi : 10.1038/s41598-017-07934-x
Brief Summary: ''A new class of reversible rigidity switching hydrogels to actively control cells is used. Actin depolarization dynamics as well as cellular responses are tracked over time.''