Author/Editor		Chaudhry, Farrukh A; Reimer, Richard J; Križaj, David; Barber, Diane
Title		Molecular analysis of system N suggests novel physiological roles in nitrogen metabolism and synaptic transmission
Type		članek
Source		Cell
Vol. and No.		Letnik 99, št. 7
Publication year		1999
Volume		str. 769-80
Language		eng
Abstract		The amino acid glutamine has a central role in nitrogen metabolism. Although the molecular mechanisms responsible for its transport across cell membranes remain poorly understood, classical amino acid transport system N appears particularly important. Using intracellular pH measurements, we have now identified an orphan protein related to a vesicular neurotransmitter transporter as system N. Functional analysis shows that this protein (SN1) involves H+ exchange as well as Na+ cotransport and, under physiological conditions, mediates glutamine efflux as well as uptake. Together with the pattern of SN1 expression, these unusual properties suggest novel physiological roles for system N in nitrogen metabolism and synaptic transmission.
Descriptors		AMINO ACID SEQUENCE ANIMALS ASTROCYTES BRAIN CARRIER PROTEINS CELL LINE CLONING, MOLECULAR GLUTAMINE HYDROGEN-ION CONCENTRATION IMMUNOHISTOCHEMISTRY MEMBRANE PROTEINS MOLECULAR SEQUENCE DATA NITROGEN ORGAN SPECIFICITY RATS SEQUENCE ALIGNMENT SODIUM SYNAPSES SYNAPTIC TRANSMISSION