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GO:0006614
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SRP-dependent cotranslational protein targeting to membrane
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The targeting of proteins to a membrane that occurs during translation and is dependent upon two key components, the signal-recognition particle (SRP) and the SRP receptor. SRP is a cytosolic particle that transiently binds to the endoplasmic reticulum (ER) signal sequence in a nascent protein, to the large ribosomal unit, and to the SRP receptor in the ER membrane. |
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GO:0008312
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7S RNA binding
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Interacting selectively and non-covalently with 7S RNA, the RNA component of the signal recognition particle (SRP). |
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GO:0048500
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signal recognition particle
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A complex of protein and RNA which facilitates translocation of proteins across membranes. |
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GO:0005786
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signal recognition particle, endoplasmic reticulum targeting
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A ribonucleoprotein particle of 325 kDa composed of a 7S (300 nucleotide) RNA molecule and a complex of six different polypeptides. This binds both to the N-terminal signal peptide for proteins destined for the endoplasmic reticulum as they emerge from the large ribosomal subunit and also to the ribosome. This binding arrests further translation thereby preventing the proteins from being released into the cytosol. The SRP-ribosome complex then diffuses to the endoplasmic reticulum where it is bound to the signal recognition particle receptor, which allows resumption of protein synthesis and facilitates the passage of the growing polypeptide chain through the translocon. Through a process involving GTP hydrolysis, the SRP-SRP receptor complex dissociates and SRP returns to the cytosol. Of the six polypeptides of SRP the 54 kDa subunit (SRP54) is the central player. It contains an N-terminal GTPase domain and a C-terminal domain that binds directly to the signal peptide and the SRP RNA. Examples of this component are found in Mus musculus, Saccharomyces cerevisiae and Arabidopsis thaliana. |
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GO:0030942
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endoplasmic reticulum signal peptide binding
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Interacting selectively and non-covalently with an endoplasmic reticulum signal peptide, a specific peptide sequence that acts as a signal to localize the protein within the endoplasmic reticulum. |
