Empty site forms of the SRP54 and SRalpha GTPases mediate targeting of ribosome-nascent chain complexes to the endoplasmic reticulum

Article Abstract:

The interaction between the signal recognition particle (SRP) and the SRP receptor in the sarcoplasmic reticulum (SR) mediates the signal sequence-dependent attachement of ribosomes to the Sec61 complex. Nucleotide binding and hydrolysis during protein translocation was also dependent on SRalpha and SRP54 guanosine triphosphatases which mediated the guanosine triphosphate hydrolysis-dependent dissociation of SRP from the receptor and permitted the reutilization of SRP and SR for subsequent targeting cycles.

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A viral movement protein prevents spread of the gene silencing signal in Nicotiana benthamiana

Article Abstract:

A viral movement protein has been found to prevent spread of the Nicotiana benthamiana gene-silencing signal, as demonstrated with potato virus X. In plants viruses induce RNA-mediated defence much like posttranscriptional gene silencing (PTGS). A branch common to virus-and transgene-induced PTGS is blocked by the 25kDa viral movement protein (p25). Likely it generates the systemic silencing signal. No systemic silencing was detected unless p25 was inactivated.

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Role of Sec61alpha in the regulated transfer of the ribosome-nascent chain complex from the signal recognition particle to the translocation channel

Article Abstract:

Results demonstrate that Sec61alpha is a structural core of the protein translocation channel of the mammalian endoplasm reticulum. Data point out that Sec61 complex has a role in regulating GTP hydrolysis of the signal recognition particle and the receptor complex.

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