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- W1982100072 abstract "The last few years has seen enormous progress in understanding of protein targeting and translocation across biological membranes. Many of the key molecules involved have been identified, isolated, and the corresponding genes cloned, opening up the way for detailed analysis of the structure and function of these molecular machines. It has become clear that the protein translocation machinery of the endoplasmic reticulum is very closely related to that of bacteria, and probably represents an ancient solution to the problem of how to get a protein across a membrane. One of the thylakoid translocation systems looks as if it will also be very similar, and probably represents a pathway inherited from the ancestral endosymbiont. It is interesting that, so far, there is a perfect correlation between thylakoid proteins which are present in photosynthetic prokaryotes and those which use the sec pathway in chloroplasts; conversely, OE16 and 23 which use the delta pH pathway are not found in cyanobacteria. To date, no Sec-related proteins have been found in mitochondria, although these organelles also arose as a result of endosymbiotic events. However, virtually nothing is known about the insertion of mitochondrially encoded proteins into the inner membrane. Is the inner membrane machinery which translocates cytoplasmically synthesized proteins capable of operating in reverse to export proteins from the matrix, or is there a separate system? Alternatively, do membrane proteins encoded by mitochondrial DNA insert independently of accessory proteins? Unlike nuclear-encoded proteins, proteins encoded by mtDNA are not faced with a choice of membrane and, in principle, could simply partition into the inner membrane. The ancestors of mitochondria almost certainly had a Sec system; has this been lost along with many of the proteins once encoded in the endosymbiont genome, or is there still such a system waiting to be discovered? The answer to this question may also shed light on the controversy concerning the sorting of the inter-membrane space proteins cytochrome c1 and cytochrome b2, as the conservative-sorting hypothesis would predict re-export of matrix intermediates via an ancestral (possibly Sec-type) pathway. Whereas the ER and bacterial systems clearly share homologous proteins, the protein import machineries of mitochondria and chloroplasts appear to be analogous rather than homologous. In both cases, import occurs through contact sites and there are separate translocation complexes in each membrane, however, with the exception of some of the chaperone molecules, the individual protein components do not appear to be related. Their similarities may be a case of convergent rather than divergent evolution, and may reflect what appear to be common requirements for translocation, namely unfolding, a receptor, a pore complex and refolding. There are also important differences. Translocation across the mitochondrial inner membrane is absolutely dependent upon delta psi, but no GTP requirement has been identified. In chloroplasts the reverse is the case. The roles of delta psi and GTP, respectively, remain uncertain, but it is tempting to speculate that they may play a role in regulating the import process, perhaps by controlling the assembly of a functional translocation complex. In the case of peroxisomes, much still remains to be learned. Many genes involved in peroxisome biogenesis have been identified but, in most cases, the biochemical function remains to be elucidated. In this respect, understanding of peroxisome biogenesis is at a similar stage to that of the ER 10 years ago. The coming together of genetic and biochemical approaches, as with the other organelles, should provide many of the answers." @default.
- W1982100072 created "2016-06-24" @default.
- W1982100072 creator A5007485808 @default.
- W1982100072 creator A5019296034 @default.
- W1982100072 creator A5030626494 @default.
- W1982100072 date "1996-11-01" @default.
- W1982100072 modified "2023-10-14" @default.
- W1982100072 title "PROTEIN TARGETING AND TRANSLOCATION; A COMPARATIVE SURVEY" @default.
- W1982100072 cites W101572434 @default.
- W1982100072 cites W113936184 @default.
- W1982100072 cites W1218296894 @default.
- W1982100072 cites W129364972 @default.
- W1982100072 cites W1410230233 @default.
- W1982100072 cites W145694369 @default.
- W1982100072 cites W1481266404 @default.
- W1982100072 cites W1492114650 @default.
- W1982100072 cites W1495202351 @default.
- W1982100072 cites W1497042513 @default.
- W1982100072 cites W1497875229 @default.
- W1982100072 cites W1501701976 @default.
- W1982100072 cites W1502136504 @default.
- W1982100072 cites W1502650833 @default.
- W1982100072 cites W1516426269 @default.
- W1982100072 cites W1520740851 @default.
- W1982100072 cites W1521406343 @default.
- W1982100072 cites W1521751079 @default.
- W1982100072 cites W1522623523 @default.
- W1982100072 cites W1524989206 @default.
- W1982100072 cites W1526372251 @default.
- W1982100072 cites W1528592059 @default.
- W1982100072 cites W152988100 @default.
- W1982100072 cites W1530754292 @default.
- W1982100072 cites W1539810220 @default.
- W1982100072 cites W1541846432 @default.
- W1982100072 cites W1546958121 @default.
- W1982100072 cites W1548474808 @default.
- W1982100072 cites W1551209624 @default.
- W1982100072 cites W1551563523 @default.
- W1982100072 cites W1552590528 @default.
- W1982100072 cites W1553241112 @default.
- W1982100072 cites W1554985489 @default.
- W1982100072 cites W1557173992 @default.
- W1982100072 cites W1558079148 @default.
- W1982100072 cites W1563568335 @default.
- W1982100072 cites W1565334821 @default.
- W1982100072 cites W1565483499 @default.
- W1982100072 cites W1565885119 @default.
- W1982100072 cites W1569421494 @default.
- W1982100072 cites W1571194698 @default.
- W1982100072 cites W1576501498 @default.
- W1982100072 cites W1579834701 @default.
- W1982100072 cites W1580182982 @default.
- W1982100072 cites W1584878924 @default.
- W1982100072 cites W1585721338 @default.
- W1982100072 cites W1588568344 @default.
- W1982100072 cites W1594516651 @default.
- W1982100072 cites W1604304986 @default.
- W1982100072 cites W1604605157 @default.
- W1982100072 cites W1604988710 @default.
- W1982100072 cites W1606277396 @default.
- W1982100072 cites W1627679017 @default.
- W1982100072 cites W1640690355 @default.
- W1982100072 cites W164331308 @default.
- W1982100072 cites W1649524883 @default.
- W1982100072 cites W1666130637 @default.
- W1982100072 cites W1676529550 @default.
- W1982100072 cites W168784921 @default.
- W1982100072 cites W1717988203 @default.
- W1982100072 cites W1752944627 @default.
- W1982100072 cites W1755737437 @default.
- W1982100072 cites W1764768847 @default.
- W1982100072 cites W1795404191 @default.
- W1982100072 cites W1820635160 @default.
- W1982100072 cites W1829062329 @default.
- W1982100072 cites W1834695457 @default.
- W1982100072 cites W1848544460 @default.
- W1982100072 cites W1848937193 @default.
- W1982100072 cites W188565921 @default.
- W1982100072 cites W1906945978 @default.
- W1982100072 cites W1908462512 @default.
- W1982100072 cites W1913648471 @default.
- W1982100072 cites W1946720111 @default.
- W1982100072 cites W1964657856 @default.
- W1982100072 cites W1968817362 @default.
- W1982100072 cites W1969407643 @default.
- W1982100072 cites W1969487425 @default.
- W1982100072 cites W1971132739 @default.
- W1982100072 cites W1971447046 @default.
- W1982100072 cites W1971840994 @default.
- W1982100072 cites W1973463353 @default.
- W1982100072 cites W1973538083 @default.
- W1982100072 cites W1973792741 @default.
- W1982100072 cites W1974479145 @default.
- W1982100072 cites W1976751700 @default.
- W1982100072 cites W1977388184 @default.
- W1982100072 cites W1977495264 @default.
- W1982100072 cites W1980355157 @default.
- W1982100072 cites W1980669547 @default.