Related Experiment Video
Updated: Aug 17, 2026

Analyzing Cell Surface Adhesion Remodeling in Response to Mechanical Tension Using Magnetic Beads
Published on: March 8, 2017
Calcium oscillation and phosphatidylinositol 3-kinase positively regulate integrin alpha(IIb)beta3-mediated
Der-Shan Sun1, Szecheng J Lo, Chi-Hung Lin
1Institute of Molecular and Cellular Biology, Tzu-Chi University, Hualien, Taiwan.
Abstract:
The frequency of calcium oscillation reveals the platelet activation status, however, the biological significance of the periodic calcium responses and methods of communication with other integrin-mediated signals are not clear. RGD-containing disintegrin rhodostomin coated substrates were employed to enhance platelet spreading and calcium oscillation through direct binding and clustering of the receptor integrin alpha(IIb)beta3. The results showed that the activation of phosphatidylinositol 3-kinase (PI3-K) and internal calcium pathways were crucial for alpha(IIb)beta3 outside-in signaling. PI3-K antagonists wortmannin and LY294002 inhibited disintegrin substrates and induced platelet spreading and calcium oscillation. At the same time, pretreatment of platelets with the microsomal calcium-ATPase inhibitor thapsigargin to deplete internal calcium stores severely impaired the calcium oscillation as well as PI3-K activation and spreading on disintegrin substrates. Because inhibition of one pathway could inhibit the other, our data indicates that PI3-K and calcium oscillation are synergistically operated and form a positive-feedback regulation in integrin alpha(IIb)beta3-mediated outside-in signaling.
Related Concept Videos
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.
Intracellular Signaling Affects Focal Adhesions
Some...
IP3/DAG Signaling Pathway
Calmodulin-dependent Signaling
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
Feedback Regulation of Calcium Concentration
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
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,...

