Identifiers
RhoA_GDIs*
Rho GDP dissociation inhibitor (GDI) alpha
HUGO:ARHGDIA, HGNC:678, ENTREZ:396, GENECARDS:GC17M079825, UNIPROT:P52565
Rho GDP dissociation inhibitor (GDI) beta
HUGO:ARHGDIB, HGNC:679, ENTREZ:397, GENECARDS:GC12M015094, UNIPROT:P52566
Rho GDP dissociation inhibitor (GDI) gamma
HUGO:ARHGDIG, HGNC:680, ENTREZ:398, GENECARDS:GC16P000318, UNIPROT:Q99819
Maps_Modules
HMC:ACTIVATING_INVASION_AND_METASTASIS
EMT Senescence / EMT_REGULATORS
EMT Senescence / CYTOSKELETON_POLARITY
References
PMID:9113980
RhoGDI (so-called ARHGDIA) and GDIG4 (so-called ARHGDIB) are two known GDIs for the Rho-subfamily of GTPases.
ARHGDIG is about 50 percent identical to ARHGDIA and ARHGDIB. ARHGFIG binds to CDC42 and RhoA with less affinity compared with ARHGDIA and does not bind with Rac1, Rac2, or Ras.
ARHGDIG functions as a GDI for CDC42 but with about 20 times less efficiency than ARHGDIA.
PMID:9490022
ARHGDIA,B,G are CDC42_GDIs
References
em_emtc_emtc_re707( EMT Senescence ):
PMID:9287351
ERM family (ezrin/radixin/moesin)
Direct interaction of the ARHGDI family with ERM family initiates the activation of the Rho small G protein.
PMID:10047517
Regulation of cortical structure by the ERM protein family.
PMID:12045227
Rho-dependent and -independent activation mechanisms of ERM proteins: an essential role for polyphosphoinositides in vivo.
ERM proteins crosslink actin filaments to plasma membranes and are involved in the organization of the cortical cytoskeleton, especially in the formation of microvilli.
ERM proteins are reported to be activated as crosslinkers in a Rho-dependent manner and are stabilized when phosphorylated at their C-terminal threonine residue to create C-terminal threonine- phosphorylated ERM proteins
However, ERM proteins appear to be activated in the absence of Rho activation and remain active without C-terminal phosphorylation.
Phosphatidylinositol (4,5)-bisphosphate (PtdIns(4,5)P2) affected the activation of ERM proteins regardless of cell type.
The Rho-independent activation mechanism of ERM proteins therefore exists.
Both Rho-dependent and -independent activation of ERM proteins require a local elevation of PtdIns(4,5)P2 concentration in vivo.
EMR proteins remove ARHGDIA from binding with CDC42 leading to CDC42 activation
em_emtc_emtc_re681( EMT Senescence ):
PMID:9113980
RhoGDI (so-called ARHGDIA) and GDIG4 (so-called ARHGDIB) are two known GDIs for the Rho-subfamily of GTPases.
ARHGDIG is about 50 percent identical to ARHGDIA and ARHGDIB. ARHGFIG binds to CDC42 and RhoA with less affinity compared with ARHGDIA and does not bind with Rac1, Rac2, or Ras.
ARHGDIG functions as a GDI for CDC42 but with about 20 times less efficiency than ARHGDIA.
PMID:9490022
ARHGDIA,B,G are CDC42_GDIs
em_emtc_emtc_re693( EMT Senescence ):
PMID:11149925
2 classes of negative regulators of Rho proteins have been described. GAPs and GDIs.
Rho proteins have relatively slow intrinsic rates of GTP hydrolysis that can be accelerated by GAPs (GTPase activating proteins).
Another class of proteins shown to inhibit the release of GDP from Rho proteins, GDIs (GDP Dissociation Inhibitors (GDIs) have been described.
Perhaps more important than their effects on the GDP/GTP cycle is the ability of GDIs to solubilize membrane-associated Rho proteins.
RhoA is sequestered in the cytosol by a RhoGDI-dependent and -independent mechanisms.
RhoGDI binding is not affected by the length of the prenyl chain (farnesylation versus geranylgeranylation)
Palmitoylation blocks RhoGDI binding.
GDIs play a primary role in modulating the activation of GTPases and may also be critical for the cellular compartmentalization of GTPases.
em_emtc_emtc_re844( EMT Senescence ):
PMID:10816584
PMID:17045588
CDC42SE1 (SPEC1) binds to CDC42 and supresses CDC42-induced JNK activation and cytoskeleton remodeling.