Sandbox 208: Difference between revisions

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*'''An essential step: Rab prenylation'''

All Rabs undergo posttranslational modification by prenylation. Prenylation is essential for Rab function and membrane association but also for its binding to GDI.

All Rabs undergo [http://http://en.wikipedia.org/wiki/Posttranslational_modification posttranslational modification] by prenylation. Prenylation is essential for Rab function and membrane association but also for its binding to GDI.

In most cases, this post-translationally modification consists in the attachment of geranylgeranyl lipid groups on two C-terminus cysteines. Geranylgeranylation is catalyzed by the prenyltransferase, geranylgeranyltransferase type II (GGTrII), a heterodimer containing α- and β-subunits. GGTrII requires the activity of an accessory protein, Rab escort protein (REP). REP is able to bind newly synthesized Rabs and to mediate their delivery to GGTrII.

In most cases, this post-translationally modification consists in the attachment of geranylgeranyl lipid groups on two C-terminus cysteines. [http://http://en.wikipedia.org/wiki/Geranylgeranylation Geranylgeranylation] is catalyzed by the [http://http://en.wikipedia.org/wiki/Prenyltransferase prenyltransferase], geranylgeranyltransferase type II (GGTrII), a heterodimer containing α- and β-subunits. GGTrII requires the activity of an accessory protein, Rab escort protein ([http://http://en.wikipedia.org/wiki/Rab_escort_protein REP]). REP is able to bind newly synthesized Rabs and to mediate their delivery to GGTrII.

*'''GDI versus REP'''

GDI does not facilitate Rabs prenylation since it lacks the geranylgeranyl transferase binding site. It is involved in Rabs recycling. Its function consists in retrieving Rab in the GDP bound form from the membrane and delivers it to the cytosol. Thus, GDI controls the Rabs distribution between cytosol and membranes. GDI is stably associated only with GDP loaded and prenylated Rab proteins.

Both REP and GDI are considered as Rab molecular chaperones. They have similar organization, in particular, their Rab binding interface which is well conserved.

Both REP and GDI are considered as Rab molecular [http://http://en.wikipedia.org/wiki/Chaperone_(protein) chaperones]. They have similar organization, in particular, their Rab binding interface which is well conserved.

=Structure=

Sandbox 208: Difference between revisions

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@@ Line 19: / Line 19: @@
 *'''An essential step: Rab prenylation'''
-All Rabs undergo posttranslational modification by prenylation. Prenylation is essential for Rab function and membrane association but also for its binding to GDI.
+All Rabs undergo [http://http://en.wikipedia.org/wiki/Posttranslational_modification posttranslational modification] by prenylation. Prenylation is essential for Rab function and membrane association but also for its binding to GDI.
-In most cases, this post-translationally modification consists in the attachment of geranylgeranyl lipid groups on two C-terminus cysteines. Geranylgeranylation is catalyzed by the prenyltransferase, geranylgeranyltransferase type II (GGTrII), a heterodimer containing α- and β-subunits. GGTrII requires the activity of an accessory protein, Rab escort protein (REP). REP is able to bind newly synthesized Rabs and to mediate their delivery to GGTrII.
+In most cases, this post-translationally modification consists in the attachment of geranylgeranyl lipid groups on two C-terminus cysteines. [http://http://en.wikipedia.org/wiki/Geranylgeranylation Geranylgeranylation] is catalyzed by the [http://http://en.wikipedia.org/wiki/Prenyltransferase prenyltransferase], geranylgeranyltransferase type II (GGTrII), a heterodimer containing α- and β-subunits. GGTrII requires the activity of an accessory protein, Rab escort protein ([http://http://en.wikipedia.org/wiki/Rab_escort_protein REP]). REP is able to bind newly synthesized Rabs and to mediate their delivery to GGTrII.
 *'''GDI versus REP'''
 GDI does not facilitate Rabs prenylation since it lacks the geranylgeranyl transferase binding site. It is involved in Rabs recycling. Its function consists in retrieving Rab in the GDP bound form from the membrane and delivers it to the cytosol. Thus, GDI controls the Rabs distribution between cytosol and membranes. GDI is stably associated only with GDP loaded and prenylated Rab proteins.
-Both REP and GDI are considered as Rab molecular chaperones. They have similar organization, in particular, their Rab binding interface which is well conserved.
+Both REP and GDI are considered as Rab molecular [http://http://en.wikipedia.org/wiki/Chaperone_(protein) chaperones]. They have similar organization, in particular, their Rab binding interface which is well conserved.
 =Structure=