Melanophilin is a carrier protein

Carrier protein

Carrier proteins are proteins involved in the movement of ions, small molecules, or macromolecules, such as another protein, across a biological membrane. Carrier proteins are integral membrane proteins; that is they exist within and span the membrane across which they transport substances. The...

 which in humans is encoded by the MLPH 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...

. Several alternatively spliced

Alternative splicing

Alternative splicing is a process by which the exons of the RNA produced by transcription of a gene are reconnected in multiple ways during RNA splicing...

 transcript variants of this gene have been described, but the full-length nature of some of these variants has not been determined.

Function

This gene encodes a member of the exophilin subfamily of Rab effector proteins. The protein forms a ternary complex with the small Ras-related GTPase Rab27

Rab27

Rab27 is a member of the Rab subfamily of GTPases. Rab27 is post translationally modified by the addition of two geranylgeranyl groups on the two C-terminal cysteines.-Pathology:...

A in its GTP-bound form and the motor protein myosin Va. A similar protein complex in mouse functions to tether pigment-producing organelles called melanosome

Melanosome

In a biological cell, a melanosome is an organelle containing melanin, the most common light-absorbing pigment found in the animal kingdom.Cells that synthesize melanins are called melanocytes, and also the retinal pigment epithelium cells, whereas cells that have merely engulfed the melanosomes...

s to the actin

Actin

Actin is a globular, roughly 42-kDa moonlighting protein found in all eukaryotic cells where it may be present at concentrations of over 100 μM. It is also one of the most highly-conserved proteins, differing by no more than 20% in species as diverse as algae and humans...

 cytoskeleton

Cytoskeleton

The cytoskeleton is a cellular "scaffolding" or "skeleton" contained within a cell's cytoplasm and is made out of protein. The cytoskeleton is present in all cells; it was once thought to be unique to eukaryotes, but recent research has identified the prokaryotic cytoskeleton...

 in melanocytes, and is required for visible pigmentation in the hair and skin.

In melanocytic cells MLPH gene expression may be regulated by MITF

Microphthalmia-associated transcription factor

Microphthalmia-associated transcription factor is a basic helix-loop-helix leucine zipper transcription factor involved in melanocyte and osteoclast development.-Clinical significance:...

.

Clinical significance

A mutation in this gene results in Griscelli syndrome type 3

Griscelli syndrome type 3

Griscelli syndrome type 3 is a disorder of melanosome transport presenting initially with hypopigmentation....

, which is characterized by a silver-gray hair color and abnormal pigment distribution in the hair shaft.

Mutations in melanophilin cause the "dilute" coat color phenotype in dogs and cats. Variation in this gene appears to have been a target for recent natural selection

Natural selection

Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....

in humans, and it has been hypothesized that this is due to a role in human pigmentation.