1. 2013. 8. 3 LEE Byeong Gwon
Object : To know melanosome biogenesis step and transport mechanism.

3. Pmel17
an important structural
component of
melanosomes, is present
in the limiting membrane
of stage I melanosomes
then enters intralumenal
vesicles, undergoes
proteolytic cleavage
and forms the lumenal
fibrillar striations that
characterise stage II
organelles.

4. Melanosomes Are Specialized Members of the Lysosomal Lineage of
Organelles, 1995

5. Stage Ⅰ
pre-melanosomes are nonpigmented vacuoles that are
derived from the endosomal system.
Stage Ⅱ
These then acquire characteristic internal striations.
Stage Ⅲ
Melanin pigment is deposited onto the striations.
Stage Ⅳ
eventually giving rise to mature, fully melanised.

7. Powering membrane traffic in endocytosis and recycling, 2006

8. Different modes of melanin transfer
①Cytophagocytosis ②Phagocytosis
③Membrane fusion ④Vesicular transfer
①
② ③ ④

9. Cover picture
The Rab27a GTPase associates with
melanosomes and regulates their transport
to, and retention in, the peripheral
cytoplasm in skin melanocytes.
Melanosome transport also requires the
microtubule and actin cytoskeleton.
Staining of a cultured murine melanocyte
for filamentous actin (red) and
microtubules (blue) reveals a close
relationship between Rab27a-labelled
melanosomes (green) and these
cytoskeletal elements.