Lipid trigger

Annexins Internal associated with lipids, trigger... 

Bogdanov, M., Xie, J., Heacock, P. N., Dowhan, W. 2008. Operation of a lipid-triggered reversible transmembrane molecular switch within a membrane protein. J. Biol. Chem. submitted. 

In summary, treatment with 13-MTD induced no change in activity and expression of caspase-3. Furthermore, 13-MTD induced no mobilization of cellular calcium. However, 13-MTD altered mitochondrial transmembrane potential and induced AIF translocation from the mitochondria to the nucleus after 4 h of treatment. These results support the view that incorporation of 13-MTD into cellular lipids triggers apoptosis via a caspase-independent pathway. 

CC, and one CX3C and XC chemokine receptors have been cloned so far [2]. Receptor binding initiates a cascade of intracellular events mediated by the receptor-associated heterotrimeric G-proteins. These G-protein subunits trigger various effector enzymes that lead to the activation not only of chemotaxis but also to a wide range of fimctions in different leukocytes such as an increase in the respiratory burst, degranulation, phagocytosis, and lipid mediator synthesis. 

Interaction with a lipid bilayer driven by a potential difference and by polar and/or hydrophobic forces between the amino acid side chains of the pardaxin tetramers and the polar membrane lipid head group triggers insertion from a "raft" like structure. 

At cellular level each stage of atheroma development is accompanied by the expression of specific glycoproteins by endothelial cells which mediate the adhesion of monocytes and T-lymphocytes. Their recruitment and migration is triggered by various cytokines released by leukocytes and possibly by smooth muscle cells. Atheroma development continues with the activation of macrophages, which accumulate lipids and become, together with lymphocytes, so-called fatty streaks. The continuous influx, differentiation and proliferation finally leads to more advanced lesion and to the formation of the fibrous plaque. ... 

Oda, M.N., Forte, T.M., Ryan, R.O., and Voss, J.C. 2003. The C-terminal domain of apo-lipoprotein A-I contains a lipid-sensitive conformational trigger. Nature Structural Biology 10 455 -60. 

A highly stable and shielded polyplex should circulate in the blood stream without undesired interactions until it reaches the target cell. At that location, specific interactions with the cell surface should trigger intracellular uptake. While lipid membrane interaction is undesired at the cell surface, it should happen subsequently within the endosomal vesicle and mediate polyplex delivery into the cytosol. During or after intracellular transport to the site of action, the polyplex stability should be weakened to an extent that the nucleic acid is accessible to exert its function. 

Tumor tissues overexpress matrix metalloproteinases (MMPs). A liposomal pDNA carrier (MEND) was developed containing PEG conjugated to lipid via a peptide linker that is a target sequence for MMPs. In this strategy, PEG is removed from the carrier via MMP-triggered cleavage [198]. Intravenous administration in... 

Vesicular proteins and lipids that are destined for the plasma membrane leave the TGN sorting station continuously. Incorporation into the plasma membrane is typically targeted to a particular membrane domain (dendrite, axon, presynaptic, postsynaptic membrane, etc.) but may or may not be triggered by extracellular stimuli. Exocytosis is the eukaryotic cellular process defined as the fusion of the vesicular membrane with the plasma membrane, leading to continuity between the intravesicular space and the extracellular space. Exocytosis carries out two main functions it provides membrane proteins and lipids from the vesicle membrane to the plasma membrane and releases the soluble contents of the lumen (proteins, peptides, etc.) to the extracellular milieu. Historically, exocytosis has been subdivided into constitutive and regulated (Fig. 9-6), where release of classical neurotransmitters at the synaptic terminal is a special case of regulated secretion [54]. 

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