About the signal peptide website:
The Introduction provides background information on the signal peptide website, especially on the generation/updates of the databases (signal sequence database and references library). Search my protein allows searching of the signal sequence database and the reference database for a particular protein of interest. Advanced database search is the tool for searching the signal sequence database on the basis of: the protein name, species or lineages, signal sequence length and/or amino acid sequence. Signal sequences databases provides a direct access to the signal sequence databases grouped into Mammalia, Drosophila, Viruses and Bacteria. The References Library is a database containing references and can be searched by protein name, author, and/or keywords.
N-terminal signal sequences mediate targeting of nascent secretory and membrane proteins to the endoplasmic reticulum (ER) in a signal recognition particle (SRP)-dependent manner. Signal sequences have a tripartite structure, consisting of a hydrophobic core region (h-region) flanked by an n- and c-region. The latter contains the signal peptidase (SPase) consensus cleavage site. Usually, signal sequences are cleaved off co-translationally, the resulting cleaved signal sequences are termed signal peptides.
Signal sequences are extremely variable, both in their length and in their amino acid composition. This variability suggests that ER targeting and the steps beyond, i.e. translocation, signal peptidase cleavage etc. are affected by the signal sequence. Secondly, this variability may account for additional functions, i.e. post-targeting functions. Some signal peptides are further processed by an intramembrane cleaving protease called signal peptide peptidase (SPP), and the resulting N-terminal signal peptide fragments are released into the cytosol. Alternatively, signal peptides remain membrane-inserted or are released from the ER membrane.These signal peptides or signal peptide fragments are known to have diverse functions, either together with or independent of their corresponding mature proteins.
1.) von Heijne G. (1983) Patterns of amino acids near signal-sequence cleavage sites. Eur J Biochem 133 (1) 17-21
2.) Martoglio B. and Dobberstein B. (1998) Signal sequences: More than just greasy peptides. Trends Cell Biol 8 (10), 410-5
3.) Hegde R.S. and Bernstein H.D. (2006) The surprising complexity of signal sequences. Trends Biochem Sci 31(10), 563-71
4.) Dultz E., Hildenbeutel M., Martoglio B., Hochman J., Dobberstein B. and Kapp K. (2008) The signal peptide of the mouse mammary tumor virus Rem protein is released from the endoplasmic reticulum membrane and accumulates in nucleoli. J Biol Chem 283 (15) 9966-76
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