Claudin 3, also known as CLDN3, is a protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 which in humans is encoded by the CLDN3 gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

. It is a member of the claudin

Claudin

Claudins are a family of proteins that are the most important components of the tight junctions, where they establish the paracellular barrier that controls the flow of molecules in the intercellular space between the cells of an epithelium...

 protein family.

Tight junction

Tight junction

Tight junctions, or zonula occludens, are the closely associated areas of two cells whose membranes join together forming a virtually impermeable barrier to fluid. It is a type of junctional complex present only in vertebrates...

s represent one mode of cell-to-cell adhesion

Cell adhesion

Cellular adhesion is the binding of a cell to a surface, extracellular matrix or another cell using cell adhesion molecules such as selectins, integrins, and cadherins. Correct cellular adhesion is essential in maintaining multicellular structure...

 in epithelial

Epithelium

Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...

 or endothelial

Endothelium

The endothelium is the thin layer of cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. These cells are called endothelial cells. Endothelial cells line the entire circulatory system, from the heart...

 cell sheets, forming continuous seals around cells and serving as a physical barrier to prevent solutes and water from passing freely through the paracellular

Paracellular transport

Paracellular transport refers to the transfer of substances between cells of an epithelium.It is in contrast to "transcellular transport", where the substances travel through the cell, passing through both the apical membrane and basolateral membrane....

 space. These junctions are composed of sets of continuous networking strands in the outwardly facing cytoplasmic

Cytoplasm

The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...

 leaflet, with complementary grooves in the inwardly facing extracytoplasmic leaflet. The protein encoded by this intron

Intron

An intron is any nucleotide sequence within a gene that is removed by RNA splicing to generate the final mature RNA product of a gene. The term intron refers to both the DNA sequence within a gene, and the corresponding sequence in RNA transcripts. Sequences that are joined together in the final...

-less gene, a member of the claudin

Claudin

Claudins are a family of proteins that are the most important components of the tight junctions, where they establish the paracellular barrier that controls the flow of molecules in the intercellular space between the cells of an epithelium...

 family, is an integral membrane protein

Integral membrane protein

An integral membrane protein is a protein molecule that is permanently attached to the biological membrane. Proteins that cross the membrane are surrounded by "annular" lipids, which are defined as lipids that are in direct contact with a membrane protein...

 and a component of tight junction

Tight junction

Tight junctions, or zonula occludens, are the closely associated areas of two cells whose membranes join together forming a virtually impermeable barrier to fluid. It is a type of junctional complex present only in vertebrates...

 strands. It is also a low-affinity receptor for Clostridium perfringens enterotoxin

Clostridium perfringens enterotoxin

Clostridium enterotoxins are toxins produced by Clostridium species.Clostridial species are one of the major causes of food poisoning/gastro-intestinal illnesses. They are anaerobic, gram-positive, spore-forming rods that occur naturally in the soil...

, and shares amino acid sequence

Peptide sequence

Peptide sequence or amino acid sequence is the order in which amino acid residues, connected by peptide bonds, lie in the chain in peptides and proteins. The sequence is generally reported from the N-terminal end containing free amino group to the C-terminal end containing free carboxyl group...

 similarity with a putative apoptosis-related protein found in rat.

Interactions

CLDN3 has been shown to interact

Protein-protein interaction

Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...

 with CLDN1

CLDN1

Claudin-1 is a protein that in humans is encoded by the CLDN1 gene. It belongs to the group of claudins.-Interactions:CLDN1 has been shown to interact with CLDN5 and CLDN3.-Further reading:...

 and CLDN5

CLDN5

Claudin-5 is a protein that in humans is encoded by the CLDN5 gene. It belongs to the group of claudins.-Interactions:CLDN5 has been shown to interact with CLDN1 and CLDN3.-Further reading:...

.

Further reading