A traffic signal for heterodimeric amino acid transporters to transfer from the ER to the Golgi.
Heterodimeric amino acid transporters represent a unique class of transport systems that consist of a light chain that serves as the 'transporter proper' and a heavy chain that is necessary for targeting the complex to the plasma membrane. The currently prevailing paradigm assigns no role for the light chains in the cellular processing of these transporters. In this issue of the Biochemical Journal, Sakamoto et al. provide evidence contrary to this paradigm. Their studies with the rBAT -b(0,+)AT (related to b(0,+) amino acid transporter-b(0,+)-type amino acid transporter) heterodimeric amino acid transporter show that the C-terminus of the light chain b(0,+)AT contains a sequence motif that serves as the traffic signal for the transfer of the heterodimeric complex from the endoplasmic reticulum to the Golgi. This is a novel function for the light chain in addition to its already established role as the subunit responsible for the transport activity. These new findings also seem to be applicable to other heterodimeric amino acid transporters as well.
Ganapathy
Vadivel
V
Department of Biochemistry and Molecular Biology, Medical College of Georgia, 1459 Laney Walker Blvd., Augusta, GA 30912, U.S.A. vganapat@mail.mcg.edu
D026905:Amino Acid Transport Systems / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism*; D055503:Protein Multimerization; D021381:Protein Transport; D015398:Signal Transduction
D026905:Amino Acid Transport Systems