Two distinct pathways of sorting and assembly of nuclear-encoded mitochondrial inner membrane proteins are described. In the first pathway, precursor proteins that carry amino-terminal targeting signals are initially translocated via contact sites between both mitochondrial membranes into the mitochondrial matrix. They become proteolytically processed, interact with the 60-kDa heat-shock protei...

Metabolite carrier proteins of the mitochondrial inner membrane share homology in their transmembrane domains, which also carries their targeting information. In addition, some carriers have cleavable presequences which are not essential for targeting, but have some other function before import. The cytosolic chaperones Hsc70 (heat-shock cognate 70) and Hsp90 (heat-shock protein 90) complex wit...

Schwann cells polarize their surface membranes into several biochemically and ultrastructurally discrete regions of the myelin internode. To form these membrane domains, Schwann cells must sort, transport, and target membrane proteins appropriately. In this study, microtubule disassembly, confocal microscopy, and electron microscopic immunocytochemistry were used to investigate mechanisms invol...

Water and solutes transport in epithelial tissues is an important mechanism for maintenance of the homeostasis of internal environment; volume and composition of extracellular fluid. Molecular technologies and advancement of the genome projects have identified plenty of membrane proteins that mediate epithelial transport. Membrane transport proteins can be classified into channel, solute carrie...

PoIy(thioglycoloyloxyethyl methacrylate) gel has been prepared. The reactivity of its SH groups was checked with [C]phenyl isothiocyanate. Immobilization of thiol peptides and proteins to a carrier can be performed after its activation with 6,6'-dithiodinicotinic acid. The attached compounds can be released with 50 mmol dm dithiothreitol or can be hydrolyzed with enzymes or acids without decomp...

4'-Phosphopantetheine transferases (PPTases) transfer the 4'-phosphopantetheine moiety of coenzyme A onto a conserved serine residue of acyl carrier proteins (ACPs) of fatty acid and polyketide synthases as well as peptidyl carrier proteins (PCPs) of nonribosomal peptide synthetases. This posttranslational modification converts ACPs and PCPs from their inactive apo into the active holo form. We...

The effects of mobility corrections on carrier ampholytes are studied at various ampholyte concentrations to understand protein behavior during IEF. IEF simulations are conducted in the presence of 25 biprotic carrier ampholytes within a pH range of 6-9 after applying the Onsager-Debye-Hückel correction to the carrier ampholytes. Two model proteins with ten charge states but without ionic stren...

Sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) are bioactive signaling lysophospholipids that activate specific G protein-coupled receptors on the cell surface triggering numerous biological events. In circulation, S1P and LPA associate with specific carrier proteins or chaperones; serum albumin binds both S1P and LPA while HDL shuttles S1P via interactions with apoM. We used a s...