Related Experiment Videos
Modulation of calcium mobilization by guanosine 5'-O-(2-thiodiphosphate) in Xenopus oocytes
S C Sealfon1, S Mundamattom, B Gillo
1Fishberg Center in Neurobiology, Mount Sinai School of Medicine, New York, NY 10029.
Abstract:
We investigated the effect of intracellular loading of the non-hydrolyzable guanosine 5'-diphosphate analogue GDP beta S on calcium mobilization by IP3 and on calcium influx in Xenopus oocytes. Assayed by two electrode voltage-clamp recording, GDP beta S-loaded oocytes demonstrated a marked augmentation of the fast component of the response to IP3 injection, an attenuation of the slow component and an increase in membrane calcium permeability. These effects on calcium mobilization suggest that GDP beta S may facilitate calcium translocation both across the plasma membrane and between different intracellular calcium pools.
Insights
Intracellular loading of guanosine 5'-diphosphate analogue (GDP beta S) in Xenopus oocytes enhanced fast calcium mobilization by inositol trisphosphate (IP3) and increased membrane calcium permeability. This suggests GDP beta S influences calcium movement across membranes and between intracellular stores.
Area of Science:
- Cellular Biology
- Molecular Physiology
- Biochemistry
Background:
- Calcium ions (Ca2+) are critical second messengers regulating numerous cellular processes.
- Inositol trisphosphate (IP3) is a key signaling molecule that mobilizes intracellular calcium stores.
- Understanding the regulation of calcium influx and mobilization is crucial for cellular function.
Purpose of the Study:
- To investigate the impact of intracellular guanosine 5 omino-diphosphate beta-sulfate (GDP beta S) loading on calcium mobilization.
- To determine the effect of GDP beta S on calcium influx and IP3-mediated calcium release in Xenopus oocytes.
Main Methods:
- Xenopus oocytes were loaded with GDP beta S.
- Two-electrode voltage-clamp recording was employed to assay electrophysiological responses.
- Calcium mobilization and membrane permeability were measured following IP3 injection.
Main Results:
- GDP beta S loading significantly augmented the fast component of the IP3 response.
- A notable attenuation of the slow component of the IP3 response was observed.
- An increase in membrane calcium permeability was detected in GDP beta S-loaded oocytes.
Conclusions:
- GDP beta S influences the dynamics of calcium release and uptake.
- The findings suggest GDP beta S facilitates calcium translocation across the plasma membrane.
- GDP beta S may play a role in regulating calcium movement between intracellular pools.