Melanocyte protein PMEL also known as premelanosome protein (PMEL) or silver locus protein homolog (SILV) is a
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, respo ...
that in humans is encoded by the ''PMEL''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
.
Its gene product may be referred to as PMEL, silver, ME20, gp100 or Pmel17.
Structure and function
PMEL is a 100 kDa
type I Type 1 or Type I or ''variant'', may refer to:
Health
*Diabetes mellitus type 1 (also known as "Type 1 Diabetes"), insulin-dependent diabetes
* Type I female genital mutilation
* Type 1 personality
*Type I hypersensitivity (or immediate hypersensit ...
transmembrane glycoprotein that is expressed primarily in pigment cells of the skin and eye. The transmembrane form of PMEL is modified in the secretory pathway by elaboration of N-linked
oligosaccharide
An oligosaccharide (/ˌɑlɪgoʊˈsækəˌɹaɪd/; from the Greek ὀλίγος ''olígos'', "a few", and σάκχαρ ''sácchar'', "sugar") is a saccharide polymer containing a small number (typically two to ten) of monosaccharides (simple sugar ...
s and addition and modification of O-linked oligosaccharides. It is then targeted to precursors of the pigment organelle, the
melanosome, where it is
proteolytically processed to several small fragments. Some of these fragments form non-pathological
amyloid that assemble into sheets and form the striated pattern that underlies
melanosomal ultrastructure. PMEL cleavage is mediated by several proteases including a
proprotein convertase Proprotein convertases (PPCs) are a family of proteins that activate other proteins. Many proteins are inactive when they are first synthesized, because they contain chains of amino acids that block their activity. Proprotein convertases remove thos ...
of the
furin family, a "sheddase" that might include members of the
a disintegrin and metalloproteinase (ADAM) family, and additional proteases in melanosomes or their precursors. After the amyloidogenic region is cleaved, the small remaining integral membrane fragment is digested by
γ-secretase.
The expression of the PMEL gene is regulated by the
microphthalmia-associated transcription factor
Microphthalmia-associated transcription factor also known as class E basic helix-loop-helix protein 32 or bHLHe32 is a protein that in humans is encoded by the ''MITF'' gene.
MITF is a basic helix-loop-helix leucine zipper transcription factor ...
(MITF).
References
Further reading
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External links
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