Involucrin 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...

 that in humans is encoded by the IVL 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...

.

Gene

This gene is mapped to 1q21, among calpactin

S100A10

S100-A10, also known as p11, is a protein that is encoded by the S100A10 gene in humans and the S100a10 gene in other species. S100-A10 is a member of the S100 family of proteins containing two EF-hand calcium-binding motifs. S100 proteins are localized in the cytoplasm and/or nucleus of a wide...

 I light chain, trichohyalin, profillaggrin, loricrin, and calcyclin.

Function

Involucrin, a component of the keratinocyte

Keratinocyte

Keratinocytes are the predominant cell type in the epidermis, the outermost layer of the human skin, constituting 95% of the cells found there. Those keratinocytes found in the basal layer of the skin are sometimes referred to as "basal cells" or "basal keratinocytes"...

 crosslinked envelope, is found in the cytoplasm and crosslinked to membrane proteins by transglutaminase. This gene is mapped to 1q21, among calpactin I light chain, trichohyalin, profillaggrin, loricrin, and calcyclin.

Involucrin is synthesised in the stratum spinosum

Stratum spinosum

The stratum spinosum is a layer of the epidermis found between the stratum granulosum and stratum basale. This layer is also referred to as the "spinous" or "prickle-cell" layer. This appearance is due to desmosomal connections of adjacent cells. Keratinization begins in the stratum spinosum....

 and cross linked in the stratum granulosum

Stratum granulosum

The stratum granulosum is a thin layer of cells in the epidermis. Keratinocytes migrating from the underlying stratum spinosum become known as granular cells in this layer...

 by the transglutaminase

Transglutaminase

Transglutaminases are a family of enzymes that catalyze the formation of a covalent bond between a free amine group and the gamma-carboxamid group of protein- or peptide-bound glutamine. Bonds formed by transglutaminase exhibit high resistance to proteolytic degradation.Transglutaminases were...

enzyme that makes it highly stable. Thus it provide structural support to the cell, thereby allowing the cell to resist invasion by micro-organism.

Further reading