Repetin is an

extracellular matrix In biology, the extracellular matrix (ECM), also called intercellular matrix, is a three-dimensional network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide s ...

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

expressed in the epidermis. In humans it is encoded by the ''RPTN'' gene. Repetin is part of the

S100 fused-type protein S1, S01, S.I, S-1, S.1, Š-1 or S 1 may refer to: Biology and chemistry * S1 nuclease, an enzyme that digests singled-stranded DNA and RNA * S1: Keep locked up, a safety phrase in chemistry * Primary somatosensory cortex, also known as S1 * Tegaf ...

family and contains an

EF hand The EF hand is a helix–loop–helix structural domain or ''motif'' found in a large family of calcium-binding proteins. The EF-hand motif contains a helix–loop–helix topology, much like the spread thumb and forefinger of the human hand, i ...

structural domain. It functions in the cornified

cell envelope The cell envelope comprises the inner cell membrane and the cell wall of a bacterium. In gram-negative bacteria an outer membrane is also included. This envelope is not present in the Mollicutes where the cell wall is absent. Bacterial cell env ...

formation. It is a multifunctional

epidermal The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water relea ...

matrix protein. RPTN reversibly binds

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...

. RPTN is 5,634 bases long. It starts 152,126,071 base pairs from pter. It ends 152,131,704 base pairs from pter. It has a minus strand orientation. RPTN is one of the genes that differ between present-day humans and

Neanderthal Neanderthals (, also ''Homo neanderthalensis'' and erroneously ''Homo sapiens neanderthalensis''), also written as Neandertals, are an extinct species or subspecies of archaic humans who lived in Eurasia until about 40,000 years ago. While the ...

s. RPTN helps protect skin cells, and since the Neanderthals were missing this protein, the Neanderthals were better adapted to the cold, but less so to disease.

References

{{Reflist S100 fused-type proteins