Translocation of proteins

Translocation of Proteins to Their Correct Intramitochondrial Location 140... 

Craig, E.A. (1990). Role of hsp70 in translocation of proteins across membranes. In Stress Proteins in Biology and Medicine (Morimoto, R., Tissieres, A.. Georgopoulos, C., eds.), pp. 279-286, CSHL Press, Cold Spring Harbor. 

Farkade VD, Harrison STL, Pandit AB (2005) Heat induced translocation of proteins and enzymes within the cells an effective way to optimize the microbial cell disruption process. Biochem Eng J 23 247-257... 

Walter, P., and Blobel, G. (1981a). Translocation of proteins across the endoplasmic reticulum III. Signal recognition protein (SRP) causes signal sequence-dependent and site-specific arrest of chain elongation that is released by microsomal membranes. J. Cell Biol. 91, 557-561. 

Bradley PJ, Lahti CJ, Plumper E, Johnsons PJ. 1997. Targeting and translocation of proteins into the hydrogenosome of the protist Trichomonas similarities with mitochondrial protein import. EMBO J 16 3484-93. 

O Driscoll KR, Teng KK, Fabbro D, Greene LA, Weinstein IB (1995) Selective translocation of protein kinase C-delta in PC12 cells during nerve growth factor-induced neuritogenesis. Mol Biol Cell 6 449-458 Ohmi Y, Ohta A, Sasakura Y, Sato N, Yahata T, Santa K, Habu S, Nishimura T (1997) The role of phorbol ester-sensitive protein kinase C isoforms in lymphokine-activated killer cell-mediated cytotoxicity dissociation between perforin-dependent and Fas-dependent c otoxicity. Biochem Biophys Res Commun 235 461-464... 

Translocation of protein kinases is a specific process, encompassing at least two mechanisms to decide the location in the cell at which the kinase will become active. In one mechanism, sequence sections of the protein kinase are used as leader sequences for compartmentalization. 

Hydroquinone (50 (.miol/L) induced a cytosol-to-membrane translocation of protein kinase C, followed by inactivation of the enzyme activity, in cultured LL/2 lung carcinoma cells (Gopalakrishna et al., 1994). 

It had often been assumed that a hydrophobic signal sequence, perhaps folded into a hairpin loop, spontaneously inserts itself into an ER membrane to initiate translocation. However, study of the genetics of protein transport suggests otherwise. Over 50 different genetic loci affect the translocation of proteins in yeast.31/32/33d Products of these secretory genes,... 

Liu Y, Ytrehus K, Downey JM (1994) Evidence that translocation of protein kinase C is a key event during ischemic preconditioning of rabbit myocardium. J Mol Cell Cardiol 26(5) 661-668... 

RNA polymerase III (RNA Pol III) is also located in the nucleoplasm. It transcribes the genes for tRNA, 5S rRNA, U6 snRNA, and the 7S RNA associated with the signal recognition particle (SRP) involved in the translocation of proteins across the endoplasmic reticulum membrane (see Topic H4). 

Simonis, G., Weinbrenner, C., and Strasser, R.H. 2003. Ischemic preconditioning promotes a transient, but not sustained translocation of protein kinase C and sensitization of adenylyl cyclase. Basic Res. Cardiol. 98 104-113. 

Kawata, H., Yoshida, K., Kawamoto, A., Kurioka, H., Takase, E., et al. 2001. Ischemic preconditioning upregulates vascular endothelial growth factor mRNA expression and neovascularization via nuclear translocation of protein kinase C epsilon in the rat ischemic myocardium. Circ. Res. 88 696-704. 

Kobayashi H, Sugino D, Terao T. Urinary trypsin inhibitor, a Kunitz-type protease inhibitor, modulates tumor necrosis factor-stimulated activation and translocation of protein kinase C in U937 cells. Int J Oncol 1998 12 95-105. 

Translocation of Proteins Across Membranes. The transfer of proteins across biological membranes generally involves a hydrolytic modification step of the precursor form of the mature protein. This processing has been shown clearly to occur during segregation of secretory proteins, transport of proteins into mitochondria, and entry of plant and microbial toxins into cells as shown in Table XII. 

Table XII. Some Factors in Translocation of Proteins Across Membranes...

There is also evidence that the stress-70 proteins interact with extended, or unfolded, polypeptides. It has been demonstrated that a mitochondrial stress-70 protein is essential for import of proteins into mitochondria (Kang et al., 1990 Ostermann 1990). More specifically, polypeptides bind to, and can be cross-linked to, the mitochondrial stress-70 protein during import (Scherer et ai, 1990). It has further been demonstrated that cytoplasmic stress-70 proteins are essential for efficient transmembrane translocation of proteins into mitochondria or mi-crosomes (Chirico et al, 1988 Deshaies et al, 1988) this has led to the suggestion that the cytoplasmic stress-70 proteins may bind to and stabilize extended, unfolded conformations of polypeptide prior to their transmembrane translocation. 

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