Related Experiment Video
Updated: Jul 15, 2026
07:51
Pull-down of Calmodulin-binding Proteins
Published on: January 23, 2012
Calcium transport across the plasma membrane: stimulation by calmodulin
Science (New York, N.Y.)
|April 20, 1979
Summary
Red blood cell calcium transport is regulated by a protein activator, identical to calmodulin, which also activates cyclic nucleotide phosphodiesterase. This finding suggests a key role for this cytoplasmic protein in managing calcium levels within the cell membrane.
Area of Science:
- Biochemistry
- Cell Biology
- Membrane Transport
Background:
- Calcium ions (Ca2+) are crucial intracellular messengers.
- Plasma membrane calcium transport regulates cellular Ca2+ homeostasis.
- Red blood cells possess a Ca2+-activated, Mg2+-dependent ATPase involved in calcium extrusion.
Purpose of the Study:
- To investigate the identity of the protein activator of red blood cell calcium transport.
- To determine if red blood cell activator is similar to calmodulin.
- To explore the role of this activator in regulating plasma membrane calcium transport.
Main Methods:
- Preparation of inside-out vesicles from red blood cell membranes.
- Assay of active calcium transport into these vesicles.
- Purification and characterization of the protein activator from red cell hemolysates.
- Comparison of the red blood cell activator with purified bovine brain calmodulin.
Main Results:
- The purified red blood cell activator stimulated active calcium transport into vesicles.
- Calmodulin also equally stimulated active calcium transport into the same vesicles.
- These findings indicate the identity between the red blood cell activator and calmodulin.
Conclusions:
- The protein activator of red blood cell calcium transport is identical to calmodulin.
- Calmodulin, a known activator of cyclic nucleotide phosphodiesterase, also regulates plasma membrane calcium transport in red blood cells.
- This cytoplasmic protein plays a significant role in the regulation of calcium homeostasis at the plasma membrane.
Related Concept Videos
01:09Cell Migration
Cell migration, the process by which cells move from one location to another, is essential for the proper development and viability of organisms throughout their life. When cells are not able to migrate properly to their ordained locations, various disorders may occur. For example, disruption in cell migration causes chronic inflammatory diseases such as arthritis.
01:16Cell Motility through Blebbing
Blebs are a type of membrane protrusion formed by the internal hydrostatic pressure of the cytoplasm. Blebs are observed in several cell types, including fibroblasts, immune cells, and single-celled organisms like the amoeba. The primary function of blebs is cell locomotion and apoptosis, but they are also found during necrosis and cell division. The life cycle of a bleb comprises an initiation phase followed by the expansion and retraction phases.
Blebbing Through the Matrix
In multicellular...
Blebbing Through the Matrix
In multicellular...
01:19Membrane Asymmetry Regulating Transporters
Enzymes like flippase, floppase, and scramblase transfer phospholipids from one layer to another in the membrane, thereby affecting membrane asymmetry.
Flippase
Eukaryotic flippases are type-IV P-type ATPases or P4-ATPases belonging to P-type ATPase family proteins that are membrane-bound pumps involved in the ATP-mediated transport of ions and molecules across the membrane. Flippases flip specific phospholipids from the outer to the inner leaflet of a membrane. All P4-ATPases have one...
Flippase
Eukaryotic flippases are type-IV P-type ATPases or P4-ATPases belonging to P-type ATPase family proteins that are membrane-bound pumps involved in the ATP-mediated transport of ions and molecules across the membrane. Flippases flip specific phospholipids from the outer to the inner leaflet of a membrane. All P4-ATPases have one...
01:16Calmodulin-dependent Signaling
Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
01:17Intracellular Signaling Affects Focal Adhesions
Integrins act both as extracellular input receivers and as intracellular processing activators. As their name suggests, integrins are entirely integrated into the membrane structure. Their hydrophobic membrane-spanning regions interact with the phospholipid bilayer's hydrophobic region. These membrane receptors provide extracellular attachment sites for effectors like hormones and growth factors. They activate intracellular response cascades when their effectors are bound and active.
Some...
Some...
01:25Smooth Muscle Contraction
Smooth muscle contraction is a complex process vital for various bodily functions, from maintaining blood vessel tension to facilitating the movement of food through the digestive tract. Unlike striated muscles, smooth muscle contraction begins more slowly and lasts longer.
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...