2001
DOI: 10.1074/jbc.m104584200
|View full text |Cite
|
Sign up to set email alerts
|

Escherichia coli SecA Helicase Activity Is Not Required in Vivo for Efficient Protein Translocation or Autogenous Regulation

Abstract: SecA is an essential ATP-driven motor protein that binds to preproteins and the translocon to promote protein translocation across the eubacterial plasma membrane. Escherichia coli SecA contains seven conserved motifs characteristic of superfamily II of DNA and RNA helicases, and it has been shown previously to possess RNA helicase activity. SecA has also been shown to be an autogenous repressor that binds to its translation initiation region on secM-secA mRNA, thereby blocking and dissociating 30 S ribosomal … Show more

Help me understand this report

Search citation statements

Order By: Relevance

Paper Sections

Select...
2
1
1

Citation Types

0
14
0

Year Published

2002
2002
2018
2018

Publication Types

Select...
8
1

Relationship

0
9

Authors

Journals

citations
Cited by 20 publications
(14 citation statements)
references
References 65 publications
0
14
0
Order By: Relevance
“…Similar to CrhC, SecA possesses RNA helicase activity and is plasma membrane associated. Although the exact role that SecA driven RNA helicase activity performs in protein translocation is not known (Schmidt et al ., 2001; Sianidis et al ., 2001), it is possible that CrhC performs a function similar to that of SecA during cold acclimation in cyanobacteria. In fact, evidence has been presented indicating that the Sec‐dependent protein translocation process is cold sensitive (Pogliano and Beckwith, 1993).…”
Section: Discussionmentioning
confidence: 99%
“…Similar to CrhC, SecA possesses RNA helicase activity and is plasma membrane associated. Although the exact role that SecA driven RNA helicase activity performs in protein translocation is not known (Schmidt et al ., 2001; Sianidis et al ., 2001), it is possible that CrhC performs a function similar to that of SecA during cold acclimation in cyanobacteria. In fact, evidence has been presented indicating that the Sec‐dependent protein translocation process is cold sensitive (Pogliano and Beckwith, 1993).…”
Section: Discussionmentioning
confidence: 99%
“…More complex regulatory models can be envisioned as well; for example, the buildup of translocation intermediates of other presecretory and membrane proteins could titrate away a factor that is needed to promote the translational pause release. A role for SecA RNA helicase activity in promoting secA autoregulation has been ruled out recently, since secA helicase-defective mutants showed normal secA regulation (46). This observation precludes models in which the translational pausing agent is an RNA secondary or tertiary structure that is unwound by SecA helicase activity in order to release the secM translational pause.…”
mentioning
confidence: 99%
“…These observations suggest that Motif III allows optimal DEAD motor response to individual substrates. Remarkably, SecA Motif III is required for both RNA helicase (Park et al , 1997; Schmidt et al , 2001) and protein translocase (Fig 1E) activities. This extraordinary example of enzymatic adaptation shows that the two seemingly unrelated chemistries may be catalysed by similar DEAD motor mechanisms.…”
Section: Discussionmentioning
confidence: 99%
“…The function of this tripeptide is poorly understood (Caruthers & McKay, 2002), but it has been implicated in coupling RNA binding to helicase activity (Pause & Sonenberg, 1992; Linder et al , 2000). Motif III of SecA, however, is known to be required for its RNA helicase activity (Schmidt et al , 2001). We now examine the possible additional role of helicase Motif III (Fig 1A–C) in protein translocation.…”
Section: Introductionmentioning
confidence: 99%