What does an ARF gap cause?
Arf GAPs (ADP-ribosylation factor GTPase activating proteins) are essential components of Arf (ADP-ribosylation factor) signaling pathways. Arf GAPs stimulate the hydrolysis of GTP to GDP to transition Arf from the active, GTP bound, state to the inactive, GDP bound, state.
What are ARF GTPases?
ADP-ribosylation factor (Arf) GTPases are a subfamily of the Ras superfamily of small GTPases. Arf proteins perform diverse and critical functions in fundamental cellular processes like membrane trafficking, lipid modification, cytokinesis and cell adhesion.
What is ARF in biochemistry?
ADP ribosylation factors (ARFs) are members of the ARF family of GTP-binding proteins of the Ras superfamily. ARF family proteins are ubiquitous in eukaryotic cells, and six highly conserved members of the family have been identified in mammalian cells.
Does ARF activate p53?
ARF-Null Keratinocytes Expressing Oncogenic ras Form Squamous Cell Carcinomas. In murine fibroblasts and lymphoid cells, p19ARF appears to activate p53 as part of a protective mechanism that limits the transforming potential of mitogenic oncogenes (35).
Is Arf1 AG protein?
The Arf1 G protein is activated by guanine nucleotide exchange factors (GEFs) through their catalysis of GDP nucleotide release from Arf. Binding of the more abundant GTP in cells leads to conformational changes in the small G protein, allowing it to interact with numerous proteins called effectors.
Is Rab AG protein?
The Rab family of proteins is a member of the Ras superfamily of small G proteins. Approximately 70 types of Rabs have now been identified in humans. Rab proteins generally possess a GTPase fold, which consists of a six-stranded beta sheet which is flanked by five alpha helixes.
How does ARF inhibit MDM2?
The ability of MDM2 to target p53 for proteolytic degradation is inhibited by ARF[92],[93]. This ARF-MDM2 interaction blocks MDM2 from shuttling between the nucleus and cytoplasm and sequesters MDM2 in the nucleolus; preventing it from degrading p53 resulting in the indirect activation of p53[92]–[96].
What is a Rab effector?
Rab effectors, defined as proteins that interact specifically with the GTP-bound from of a Rab GTPase, come in many flavours and include molecular tethers, fusion regulators, motors, sorting adaptors, kinases, phosphatases, components of membrane contact sites and Rab regulators (Gillingham et al., 2014).
Where is Rab protein located?
Rab proteins form the largest branch of the Ras superfamily of GTPases. They are localized to the cytoplasmic face of organelles and vesicles involved in the biosynthetic/secretory and endocytic pathways in eukaryotic cells.
Is ATP a protein?
ATP is a nucleotide that consists of three main structures: the nitrogenous base, adenine; the sugar, ribose; and a chain of three phosphate groups bound to ribose. The phosphate tail of ATP is the actual power source which the cell taps.
What is the function of MDM2?
Mdm2 is an important negative regulator of the p53 tumor suppressor. Mdm2 protein functions both as an E3 ubiquitin ligase that recognizes the N-terminal trans-activation domain (TAD) of the p53 tumor suppressor and as an inhibitor of p53 transcriptional activation.
What does MDM2 do to p53?
The MDM2 protein is a negative regulator of p53. After binding to p53, it inhibits its transcriptional activity, favours its nuclear export and stimulates its degradation. The overexpression of MDM2 in various tumours inhibits p53, therefore favouring uncontrolled cell proliferation.
What is the Rab cycle?
The Rab GTPase cycle. The Rab GTPase switches between GDP- and GTP-bound forms, which have different conformations. Conversion from the GDP- to the GTP-bound form is caused by nucleotide exchange, catalyzed by a GDP/GTP exchange factor (GEF).
What is the function of ARF GAP?
Arf GAPs: multifunctional proteins that regulate membrane traffic and actin remodelling The ADP-ribosylation factor (Arf) Arf GTPase-activating proteins (GAPs) are a family of proteins that induce hydrolysis of GTP bound to Arf.
What is the function of ARF GTPase?
The ADP-ribosylation factor (Arf) Arf GTPase-activating proteins (GAPs) are a family of proteins that induce hydrolysis of GTP bound to Arf. A conserved domain containing a zinc finger motif mediates catalysis.
What does ARFGAP1 stand for?
ADP-ribosylation factor GTPase-activating protein 1 is an enzyme that in humans is encoded by the ARFGAP1 gene. Two transcript variants encoding different isoforms have been found for this gene.
What is the function of the ARF1 protein?
The encoded protein promotes hydrolysis of ARF1-bound GTP and is required for the dissociation of coat proteins from Golgi-derived membranes and vesicles. Dissociation of the coat proteins is required for the fusion of these vesicles with target compartments.