MELANOCYTES AND MELANOSOMES

MELANOCYTES ARE THE CELLS THAT MAKE MELANOSOMES

MELANOSOMES ARE MEMBRANE-BOUND ORGANELLES THAT

SYNTHESIZE AND STORE MELANIN

EUMELANIN IS BLACK

MELANIN IS A COMPLEX POLYMER MADE FROM TYROSINE

BUT OTHER MELANINS CAN BE YELLOW TO RED

AFRICAN/AMERICAN ASIAN CAUCASIAN

AFRICAN/AMERICAN ASIAN CAUCASIAN

11% MELANOSOMES IN MEMBRANE- BOUND PACKETS

37% MELANOSOMES IN MEMBRANE- BOUND PACKETS

85% MELANOSOMES IN MEMBRANE- BOUND PACKETS

MELANOBLASTS MIGRATE FROM THE NEURAL CREST DURING EMBRYOGENESIS

MELANOBLASTS DIVIDE TO FORM MELANOCYTES

http://z.about.com/d/skincancer/1/0/w/-/-/-/normal-mole2.jpg

LEUKODERMIA

AN AUTO - IMMUNE DISEASE IN WHICH SOME MELANOCYTES ARE DESTROYED BY THE IMMUNE SYSTEM

http://www.keratin.com/as/as001.shtml

INACTIVE TYROSINASE DUE TO MUTATION

INACTIVE TYROSINASE DUE TO MUTATION

MUTATION CAUSING SOME IMPROPER FOLDING THAT DOES NOT AFFECT TYROSINASE ACTIVITY.

BUT GOLGI QUALITY CONTROL SENDS IT BACK TO THE RER.

INACTIVE TYROSINASE DUE TO MUTATION

MUTATION CAUSING SOME IMPROPER FOLDING THAT DOES NOT AFFECT TYROSINASE ACTIVITY.

BUT GOLGI QUALITY CONTROL SENDS IT BACK TO THE RER.

CORRECT SUGARS ARE NOT ADDED TO OLIGOSACCHARIDES OF TYROSINASE.

SO MISDIRECTED AT TRANS-GOLGI SYSTEM

MAY BE PUT INTO SECRETORY VESICLES BY MISTAKE.

LACK OF TYROSINE TRANSPORT SYSTEM IN MELANOSOME MEMBRANE.

INACTIVE TYROSINASE DUE TO MUTATION

MUTATION CAUSING SOME IMPROPER FOLDING THAT DOES NOT AFFECT TYROSINASE ACTIVITY.

BUT GOLGI QUALITY CONTROL SENDS IT BACK TO THE RER.

CORRECT SUGARS ARE NOT ADDED TO OLIGOSACCHARIDES OF TYROSINASE.

SO MISDIRECTED AT TRANS-GOLGI SYSTEM

MAY BE PUT INTO SECRETORY VESICLES BY MISTAKE.

INACTIVE TYROSINASE DUE TO MUTATION

MUTATION CAUSING SOME IMPROPER FOLDING THAT DOES NOT AFFECT TYROSINASE ACTIVITY.

BUT GOLGI QUALITY CONTROL SENDS IT BACK TO THE RER.

CORRECT SUGARS ARE NOT ADDED TO OLIGOSACCHARIDES OF TYROSINASE.

SO MISDIRECTED AT TRANS-GOLGI SYSTEM

MAY BE PUT INTO SECRETORY VESICLES BY MISTAKE.

LACK OF TRANSFER TO KERATINOCYTES

LACK OF TYROSINE TRANSPORT SYTEM IN MELANOSOME MEMBRANE.

MELANSOMES ARE TAKEN UP BY PHAGOCYTOSIS INTO THE LOWER KERATINOCYTES

“MELANOSOME COMPLEX” IN KERATINOCYTE

MELANOCYTES BEING PHAGOCYTOSED BY A KERATINOCYTE

PHAGOCYTOSED MELANOSOMES ARE DISTRIBUTED

AS A CAP AT TOP OF THE NUCLEUS

LATEX BEADS TAKEN UP BY KERATINOCYTE AND FORMING A CAP ON TOP OF THE NUCLEUS

Keratinocyte Growth Factor Promotes Melanosome Transfer

to Keratinocytes

CULTURED MELANOCYTES (M) AND KERATINOCYTES (K)

MELANOSMES ARE GREEN (ANTI-TYROSINASE IMMUNOFLUORESCENCE LABELLING)

KERATINOCYTES ARE RED (ANTI-KERATIN IMMUNOFLUORESCENCE LABELLING)

CULTURED CELLS TREATED WITH KERATINOCYTE GROWTH FACTOR (KGF)

CULTURED CELLS EXPOSED TO UVB LIGHT

CULTURE TREATED WITH MELANOCYTE-STIMULATING HORMONE

(MSH)

BEGINNING OF A MALIGNANT MELANOMA (DUE TO UNCONTROLLED GROWTH OF MELANOCYTES)

LOW POWER HIGH POWER