Related Experiment Video
Updated: Jun 23, 2026

Imaging Integrin Tension and Cellular Force at Submicron Resolution with an Integrative Tension Sensor
Published on: April 25, 2019
The "hot wires" of the relaxin-like factor (Insl3)
Christian Schwabe1, Erika E Büllesbach
1Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, USA. schwabec@musc.edu
Abstract:
The discovery of the total separation of receptor-binding and signal-generating regions of the relaxin-like factor (RLF) has provided an opportunity to investigate the mechanism of transmembrane signaling. The receptor-binding residues of RLF are in the B chain of the two-chain molecule and extend from the midregion of the central helix to the tryptophan in position B27. The signal initiation site resides in two residues before the N-terminal cysteine in each chain. For optimal signaling the RLF requires five L-alpha-amino acids preceding cysteine A10, whereas the B chain requires only three. The nature of the side chains of these amino acids is not critical for the signaling function. Heuristic arguments lead us to suggest that the peptide bond is the signal-generating feature of RLF and possibly of other peptide hormones.
Related Concept Videos
Relaxation of Skeletal Muscles
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.
Actin Filament Depolymerization
In F-actin, the ADF/cofilin proteins...
Intracellular Signaling Affects Focal Adhesions
Some...
Activation of Integrins
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
Integrins
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
Cytoskeletal Linker Proteins - Plakins
