PROSITE documentation PDOC00612 [for PROSITE entry PS00756]
Protein secY signatures


The eubacterial secY protein [1] plays an important role in protein export. It interacts with the signal sequences of secretory proteins as well as with two other components of the protein translocation system: secA and secE. SecY is an integral plasma membrane protein of 419 to 492 amino acid residues that apparently contains ten transmembrane segments. Such a structure probably confers to secY a 'translocator' function, providing a channel for periplasmic and outer-membrane precursor proteins.

Homologs of secY are found in archaebacteria [2]. SecY is also encoded in the chloroplast genome of some algae [3] where it could be involved in a prokaryotic-like protein export system across the two membranes of the chloroplast endoplasmic reticulum (CER) which is present in chromophyte and cryptophyte algae.

In eukaryotes, the evolutionary related protein sec61-α plays a role in protein translocation through the endoplasmic reticulum; it is part of a trimeric complex that also consist of sec61-β and γ [4].

We have developed two signature patterns for secY proteins. The first corresponds to the second transmembrane region, which is the most conserved section of these proteins. The second spans the C-terminal part of the fourth transmembrane region, a short intracellular loop, and the N-terminal part of the fifth transmembrane region.

Last update:

December 2004 / Pattern and text revised.


Technical section

PROSITE methods (with tools and information) covered by this documentation:

SECY_2, PS00756; Protein secY signature 2  (PATTERN)

SECY_1, PS00755; Protein secY signature 1  (PATTERN)


1AuthorsIto K.
TitleSecY and integral membrane components of the Escherichia coli protein translocation system.
SourceMol. Microbiol. 6:2423-2428(1992).
PubMed ID1406280

2AuthorsAuer J. Spicker G. Boeck A.
TitlePresence of a gene in the archaebacterium Methanococcus vannielii homologous to secY of eubacteria.
SourceBiochimie 73:683-688(1991).
PubMed ID1764515

3AuthorsDouglas S.E.
TitleA secY homologue is found in the plastid genome of Cryptomonas phi.
SourceFEBS Lett. 298:93-96(1992).
PubMed ID1544427

4AuthorsHartmann E. Sommer T. Prehn S. Goerlich D. Jentsch S. Rapoport T.A.
TitleEvolutionary conservation of components of the protein translocation complex.
SourceNature 367:654-657(1994).
PubMed ID8107851

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