Membrane transport proteins targeting

Several targets like kDNA replication machinery, purine salvage pathway, purine and pyrimidine biosynthetic pathway, histone deacetylase, DNA topoisomerases, membrane transporter proteins, glycoproteins and glycolipids are discussed in this book. 

LBPs are likely to have conventional roles in the energy metabolism and transport of lipids in nematodes for membrane construction, etc. Many parasitic helminths have deficiencies in the synthesis of some lipids and so their lipid acquisition, transport and storage mechanisms clearly need to be specialized and therefore pertinent to the host-parasite relationship (Barrett, 1981). From a practical point of view, lipid transporter proteins may also be important in the delivery of anthelmintic drugs to their target most anthelmintics are hydrophobic and if they do not distribute to their site of action within the parasites by simple diffusion across and along membranes, then the parasite s own carrier proteins may be involved. 

Most transport vesicles bud off as coated vesicles, with a unique set of proteins decorating their cytosolic surface 141 GTP-binding proteins, such as the small monomeric GTPases and heterotrimeric GTPases (G proteins) facilitate membrane transport 142 SNARE proteins and Rabs control recognition of specific target membranes 143... 

Fluoroacetate undergoes a "lethal synthesis"(18) to 2-fluorocitrate which may reversibly inhibit aconitase and which irreversibly binds to a membrane-associated citrate transport protein(19,20). Insecticidal and other biocidal uses of fluoroacetate (or its metabolic precursors) received considerable attention twenty-five years ago( ) but most uses have been abandoned due to high nonspecific vertebrate toxicity of these compounds. Vfe have reported the use of o)-fluoro fatty acids and their derivatives as delayed-action toxicants for targeted... 

The hydrophilic hormones are derived from amino acids, or are peptides and proteins composed of amino acids. Hormones with endocrine effects are synthesized in glandular cells and stored there in vesicles until they are released. As they are easily soluble, they do not need carrier proteins for transport in the blood. They bind on the plasma membrane of the target cells to receptors that pass the hormonal signal on (signal transduction see p.384). Several hormones in this group have paracrine effects—i.e., they only act in the immediate vicinity of their site of synthesis (see p. 372). 

TARGETING CELL MEMBRANE PROTEINS TRANSMEMBRANE TRANSPORTER PROTEINS... 

The lipid membranes are a few nanometers thick. They contain proteins whose role is to actively transport particular target chemicals across these nonpolar barriers. The outer membranes of gram negative bacteria also have protein channels called porins that allow passage of small polar and charged substrates. 

As hormone-sensitive lipase hydrolyzes triacylglyc-erol in adipocytes, the fatty acids thus released (free fatty acids, FFA) pass from the adipocyte into the blood, where they bind to the blood protein serum albumin. This protein (Mv 66,000), which makes up about half of the total serum protein, noncovalently binds as many as 10 fatty acids per protein monomer. Bound to this soluble protein, the otherwise insoluble fatty acids are carried to tissues such as skeletal muscle, heart, and renal cortex. In these target tissues, fatty acids dissociate from albumin and are moved by plasma membrane transporters into cells to serve as fuel. 

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