Terminal inner membrane

Derouiche, R., Benedetti, H., Lazzaroni, J.C., Lazdunski, C., and Lloubes, R. (1995) Protein complex within Escherichia coli inner membrane. TolA N-terminal domain interacts with TolQ and TolR proteins./. Biol. Chem. 270, 11078-11084. 

LolA periplasmic chaperone and the LolB outer membrane receptor (Matsuyama et al., 1995 Matsuyama et al., 1997). It seems that the sorting signal of this pathway is the residue next to the amino-terminal cysteine residue of the mature part, where a fatty acid is attached. If this second residue is aspartate, the protein will remain on the inner membrane otherwise, it will be transfered to the outer membrane, although some additional structural context can affect its destiny (Yamaguchi et al., 1988 Gennity et al., 1992). 

The inner envelope membrane proteins have a cleavable N-terminal transit peptide, as well as some hydrophobic domain (s) in their mature portion. There are two possibilities on the role of this hydrophobic domain it may work as an N-terminal signal peptide after the translocation into the stroma and the subsequent cleavage of the transit peptide. Alternatively, it may work as a stop-transfer signal. One more important question is how the distinction is made between the outer membrane proteins, the inner membrane proteins, and the thylakoid membrane proteins. It is still an enigma. 

This a-helix is amphipathic, containing patches of positively charged and hydrophobic amino acids, respectively, on opposite surfaces of the theoretical cylinder. The presequence is usually processed by the mitochondrial processing peptidase (MPP) and the mature protein is sorted to either the matrix, or to the inner membrane if it bears a hydrophobic stop-transfer sequence. Some mitochondrial proteins, mostly destined to the membranes, do not have cleavable N-terminal presequences but have internal targeting signals that are not well characterized (Pfanner and Geissler 2001). 

Meier S, Neupert W, Herrmann JM (2005) Conserved N-terminal negative charges in the Timl7 subunit of the TIM23 translocase play a critical role in the import of preproteins into mitochondria. J Biol Chem 280 7777-7785 Meinecke M et al. (2006) Tim50 maintains the permeability barrier of the mitochondrial inner membrane. Science 312 1523-1526... 

The pill protein is expressed as a precursor having an amino-terminal signal peptide necessary for addressing the protein through the periplasm of E. coli. The signal peptide is removed by a specific protease after secretion, and the pill ends up anchored in the bacterial inner membrane. Its assembly in the phage particle is concomitant with phage extrusion. 

Once an electrical impulse invades the presynaptic axon terminal, it causes the release of chemical neurotransmitter stored there (Fig. 1—3). Electrical impulses open ion channels, such as voltage-gated calcium channels and voltage-gated sodium channels, by changing the ionic charge across neuronal membranes. As calcium flows into the presynaptic nerve, it anchors the synaptic vesicles to the inner membrane of the nerve terminal so that they can spill their chemical contents into the synapse. The way is paved for chemical communication by previous synthesis and storage of neurotransmitter in the first neuron s presynaptic axon terminal. 

---