Transport and transporters in the endoplasmic reticulum.
Enzyme activities localized in the luminal compartment of the endoplasmic reticulum are integrated into the cellular metabolism by transmembrane fluxes of their substrates, products and/or cofactors. Most compounds involved are bulky, polar or even charged; hence, they cannot be expected to diffuse through lipid bilayers. Accordingly, transport processes investigated so far have been found protein-mediated. The selective and often rate-limiting transport processes greatly influence the activity, kinetic features and substrate specificity of the corresponding luminal enzymes. Therefore, the phenomenological characterization of endoplasmic reticulum transport contributes largely to the understanding of the metabolic functions of this organelle. Attempts to identify the transporter proteins have only been successful in a few cases, but recent development in molecular biology promises a better progress in this field.
Csala
Miklós
M
Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary.
Marcolongo
Paola
P
Lizák
Beáta
B
Senesi
Silvia
S
Margittai
Eva
E
Fulceri
Rosella
R
Magyar
Judit E
JE
Benedetti
Angelo
A
Bánhegyi
Gábor
G
D000105:Acetyl Coenzyme A / Q000378:metabolism; D001692:Biological Transport / Q000502:physiology; D050260:Carbohydrate Metabolism / Q000502:physiology; D002331:Carnitine / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D004798:Enzymes / Q000378:metabolism*; D007700:Kinetics; D009711:Nucleotides / Q000378:metabolism; D009842:Oligopeptides / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D013379:Substrate Specificity; D013431:Sulfates / Q000378:metabolism
D002352:Carrier Proteins; D004798:Enzymes; D009711:Nucleotides; D009842:Oligopeptides; D010710:Phosphates; D013431:Sulfates; D000105:Acetyl Coenzyme A; D002331:Carnitine