Enzyme involved in lysosomal disorders has surprising role in hair pigmentation.
The enzyme UDP-GlcNAc-1-Phosphotransferase (GNPTAB) is shown by the authors of a recent study to be a clinically important enzyme in the control of human hair pigmentation. GNPTAB is an enzyme that is involved in the correct intracellular shuttling of lysosomal enzymes to lysosomes – an important organelle in cells employed in enzymatic protein processing. In disorders where this process goes wrong – so called mucolipidoses – patients have hair discoloration, which was the clue that suggested to the authors that GNPTAB was possibly involved in hair pigmentation.
Tiede et al carried out gene silencing experiments to knock out GNPTAB in whole human hair follicles and human melanocytes as well as testing a defective version of the enzyme in mice and showed that GNPTAB was in fact crucial to hair pigmentation in both humans and mice. In the melanocyte, melanin is formed in lysosomal-like structures called melanosomes by the enzyme tyrosinase. The authors suggest that that GNPTAB in melanocytes is directly controlling tyrosinase sorting into melanosomes.
Reference:
Tiede S, Hundt JE, Paus R.
‘Resident human dermal γδT-cells operate as stress-sentinels: Lessons from the hair follicle’
J Invest Dermatol. 2021 Jun 8:S0022-202X(21)01319-1. doi: 10.1016/j.jid.2021.04.028
