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New mechanism for amino acid influx into human epidermal Langerhans cells: L-dopa/proton counter-transport system.

Falck, Bengt LU ; Bendsöe, Niels LU and Ronquist, Gunnar (2003) In Experimental Dermatology 12(5). p.602-609
Abstract
We have characterized a stereospecific transport mechanism for L-dopa into human epidermal Langerhans cells (LCs). It is different from any other amino acid transport system. It is highly concentrative, largely pH-independent, and independent of exogenous Na+, glucose and oxygen, and fuelled by a renewable intracellular energy source inhibited by iodoacetate but not by arsenate. We propose that the mechanism is a unidirectional L-dopa/proton counter-transport system. We have recently demonstrated anaerobic glycolysis in human epidermis, which substantiates the need of proton pumps for resident LCs. The findings prompt a re-evaluation of the profound changes LCs undergo when exposed to oxygen in aerobic culture. L-dopa is not metabolized by... (More)
We have characterized a stereospecific transport mechanism for L-dopa into human epidermal Langerhans cells (LCs). It is different from any other amino acid transport system. It is highly concentrative, largely pH-independent, and independent of exogenous Na+, glucose and oxygen, and fuelled by a renewable intracellular energy source inhibited by iodoacetate but not by arsenate. We propose that the mechanism is a unidirectional L-dopa/proton counter-transport system. We have recently demonstrated anaerobic glycolysis in human epidermis, which substantiates the need of proton pumps for resident LCs. The findings prompt a re-evaluation of the profound changes LCs undergo when exposed to oxygen in aerobic culture. L-dopa is not metabolized by LCs but can rapidly be dislocated to the intercellular space by certain extracellular amino acids, i.e. LCs can profit by L-dopa in a dualistic way, altogether a remarkable biological phenomenon. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Experimental Dermatology
volume
12
issue
5
pages
602 - 609
publisher
Wiley-Blackwell
external identifiers
  • wos:000185198900009
  • pmid:14705800
  • scopus:0142106496
ISSN
0906-6705
DOI
10.1034/j.1600-0625.2003.00019.x
language
English
LU publication?
yes
id
128d559e-8cec-4ff4-8368-2701c08cb4f6 (old id 120344)
alternative location
http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=14705800&dopt=Abstract
date added to LUP
2007-07-03 07:57:56
date last changed
2018-05-29 12:26:14
@article{128d559e-8cec-4ff4-8368-2701c08cb4f6,
  abstract     = {We have characterized a stereospecific transport mechanism for L-dopa into human epidermal Langerhans cells (LCs). It is different from any other amino acid transport system. It is highly concentrative, largely pH-independent, and independent of exogenous Na+, glucose and oxygen, and fuelled by a renewable intracellular energy source inhibited by iodoacetate but not by arsenate. We propose that the mechanism is a unidirectional L-dopa/proton counter-transport system. We have recently demonstrated anaerobic glycolysis in human epidermis, which substantiates the need of proton pumps for resident LCs. The findings prompt a re-evaluation of the profound changes LCs undergo when exposed to oxygen in aerobic culture. L-dopa is not metabolized by LCs but can rapidly be dislocated to the intercellular space by certain extracellular amino acids, i.e. LCs can profit by L-dopa in a dualistic way, altogether a remarkable biological phenomenon.},
  author       = {Falck, Bengt and Bendsöe, Niels and Ronquist, Gunnar},
  issn         = {0906-6705},
  language     = {eng},
  number       = {5},
  pages        = {602--609},
  publisher    = {Wiley-Blackwell},
  series       = {Experimental Dermatology},
  title        = {New mechanism for amino acid influx into human epidermal Langerhans cells: L-dopa/proton counter-transport system.},
  url          = {http://dx.doi.org/10.1034/j.1600-0625.2003.00019.x},
  volume       = {12},
  year         = {2003},
}