Melanosomes

Melanosomes are transported by a bidirectional transport from the center to the tip of the melanocyte thirds. This occurs via microtubules through the motor proteins kinesin (antegrade) and dynein (retrograde). They are retained in the actin filament at the tip by binding to the myosin 5a(Myo5a) protein via the linker proteins Rab 27a and melanophilin(Mlph). If one of the members of the three-part complex (MyoVa, Rab 27a, Mlph) is defective, melanosome transport is impaired, which leads to a perinuclear accumulation of melanosomes, resulting in hypopigmentation of the skin and silvery-gray hair.

In all three types of Griscinelli syndrome, there are disorders of one of these transport proteins with silvery-gray hair, pale skin with a persistent tendency to tan when exposed to sunlight and eye changes as a result of the pigment reduction.