A protein whose binding to Na,K-ATPase is regulated by ouabain
N V Dolgova1, Iu V Kamanina, O A Akimova
1Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119992, Russia.
Biochemistry. Biokhimiia
|October 10, 2007
Summary
Researchers identified a novel melittin-like protein (MLP) interacting with Na,K-ATPase in mouse kidneys. This protein
Area of Science:
- Biochemistry
- Molecular Biology
- Cellular Physiology
Background:
- The Na,K-ATPase is a crucial ion pump involved in maintaining cellular homeostasis.
- Interactions between Na,K-ATPase and other proteins are vital for its function and regulation.
Purpose of the Study:
- To identify and characterize novel proteins interacting with the Na,K-ATPase alpha1-subunit.
- To investigate the functional significance of these interactions.
Main Methods:
- Immunoprecipitation using antibodies against Na,K-ATPase alpha1-subunit and melittin-like protein (MLP).
- Immunoaffinity chromatography for MLP purification.
- Fluorescence-based assays to assess MLP's effect on Na,K-ATPase activity.
- Edman degradation and protein sequence database analysis.
Main Results:
- A 67 kDa melittin-like protein (MLP) was found to co-precipitate with Na,K-ATPase, particularly in the presence of ouabain.
- MLP was purified and shown to modulate the fluorescence of FITC-labeled Na,K-ATPase in response to Na+ and K+ concentrations.
- The N-terminal sequence of MLP did not match known proteins, but shared homology with WD40 repeat-containing proteins.
Conclusions:
- A novel protein, MLP, interacts with Na,K-ATPase and may influence its ion transport activity.
- MLP might be a novel regulatory protein of Na,K-ATPase or a proteolysis product of a larger protein family.
- Further studies are needed to elucidate the precise role and mechanism of MLP in kidney function.
Related Concept Videos
01:29Primary Active Transport
In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction they would not...
01:47Primary Active Transport
In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps that are embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction they...
01:19Allosteric Proteins-ATCase
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
01:48ATP Synthase: Mechanism
In animals, the mitochondrial F1F0 ATP synthase is the key protein that synthesizes ATP molecules through a complex catalytic mechanism. While the nuclear genome encodes the majority of ATP synthase subunits, the mitochondrial genome encodes some of the enzyme's most critical components. The formation of this multi-subunit enzyme is a complex multi-step process regulated at the level of transcription, translation, and assembly. Defects in one or more of these steps can result in decreased ATP...
01:30ATP Driven Pumps III: V-type Pumps
V-type pumps are ATP-driven pumps found in the vacuolar membranes of plants, yeast, endosomal and lysosomal membranes of animal cells, plasma membranes of a few specialized eukaryotic cells, and some prokaryotes. They are also known as the V1Vo-ATPase, that couple ATP hydrolysis to transport protons against a concentration gradient.
The peripheral or cytosolic V1 domain with eight subunits is involved in ATP hydrolysis. The integral or transmembrane V0 domain containing at least five subunits...
The peripheral or cytosolic V1 domain with eight subunits is involved in ATP hydrolysis. The integral or transmembrane V0 domain containing at least five subunits...
01:34ATP Driven Pumps II: P-type Pumps
The P-type pumps are a large family of integral membrane transporter ATPases. They are divided into five major types based on substrate specificity, from I to V.
A typical P-type pump has three cytosolic domains: nucleotide-binding (N), phosphorylation (P), and activator (A) domains. These domains are connected to the membrane-spanning helices by short amino acid segments. ATP hydrolysis and covalent phosphoenzyme intermediate formation are crucial parts of the catalytic cycle. At the highly...
A typical P-type pump has three cytosolic domains: nucleotide-binding (N), phosphorylation (P), and activator (A) domains. These domains are connected to the membrane-spanning helices by short amino acid segments. ATP hydrolysis and covalent phosphoenzyme intermediate formation are crucial parts of the catalytic cycle. At the highly...