Rap GTP-binding protein
Encyclopedia
Rap GTP-binding protein also known as Ras-related proteins or simply RAP is a type of small GTPase
, similar in structure to Ras.
These proteins share approximately 50% amino acid identity with the classical RAS proteins and have numerous structural features in common. The most striking difference between RAP proteins and RAS proteins resides in their 61st amino acid: glutamine
in RAS is replaced by threonine
in RAP proteins. RAP counteracts the mitogenic function of RAS because it can interact with RAS GAPs and RAF in a competitive manner.
Small GTPase
Small GTPases are a family of hydrolase enzymes that can bind and hydrolyze guanosine triphosphate . They are a form of G-proteins found in the cytosol which are homologous to the alpha subunit of heterotrimeric G-proteins, but unlike the alpha subunit of G proteins, a small GTPase can function...
, similar in structure to Ras.
These proteins share approximately 50% amino acid identity with the classical RAS proteins and have numerous structural features in common. The most striking difference between RAP proteins and RAS proteins resides in their 61st amino acid: glutamine
Glutamine
Glutamine is one of the 20 amino acids encoded by the standard genetic code. It is not recognized as an essential amino acid but may become conditionally essential in certain situations, including intensive athletic training or certain gastrointestinal disorders...
in RAS is replaced by threonine
Threonine
Threonine is an α-amino acid with the chemical formula HO2CCHCHCH3. Its codons are ACU, ACA, ACC, and ACG. This essential amino acid is classified as polar...
in RAP proteins. RAP counteracts the mitogenic function of RAS because it can interact with RAS GAPs and RAF in a competitive manner.
Family members
Human genes that encode Ras-related proteins include:- RAP1ARAP1ARas-related protein Rap-1A is a protein that in humans is encoded by the RAP1A gene.- Function :The product of this gene belongs to the family of Ras-related proteins. These proteins share approximately 50% amino acid identity with the classical RAS proteins and have numerous structural features in...
, RAP1BRAP1BRas-related protein Rap-1b, also known as GTP-binding protein smg p21B, is a protein that in humans is encoded by the RAP1B gene.... - RAP2ARAP2ARas-related protein Rap-2a is a protein that in humans is encoded by the RAP2A gene. RAP2A is a member of the Ras-related protein family.-Interactions:RAP2A has been shown to interact with RUNDC3A, RASSF5 and RALGDS.-Further reading:...
, RAP2BRAP2BRas-related protein Rap-2b is a protein that in humans is encoded by the RAP2B gene. RAP2B belongs to the Ras-related protein family.-Further reading:...
, RAP1C - RAB5CRAB5CRas-related protein Rab-5C is a protein that in humans is encoded by the RAB5C gene. RAB5C belongs to the Ras-related protein family.-Further reading:...