Blood 2005,
PMID: 15632203
Schultess, Jan; Danielewski, Oliver; Smolenski, Albert P
The Ras-like guanine-nucleotide-binding protein Rap1 controls integrin alpha(IIb)beta3 activity and platelet aggregation. Recently, we have found that Rap1 activation can be blocked by the nitric oxide/cyclic guanosine monophosphate (NO/cGMP) signaling pathway by type 1 cGMP-dependent protein kinase (cGKI). In search of possible targets of NO/cGMP/cGKI, we studied the expression of Rap1-specific GTPase-activating proteins (GAPs) and guanine nucleotide exchange factors (GEFs) in platelets. We could detect mRNAs for a new protein most closely related to Rap1GAP and for postsynaptic density-95 discs-large and zona occludens protein 1 (PDZ)-GEF1 and CalDAG-GEFs I and III. Using 5'-rapid amplification of cDNA ends (RACE), we isolated the complete cDNA of the new GAP encoding a 715-amino acid protein, which we have termed Rap1GAP2. Rap1GAP2 is expressed in at least 3 splice variants, 2 of which are detectable in platelets. Endogenous Rap1GAP2 protein partially colocalizes with Rap1 in human platelets. In transfected cells, we show that Rap1GAP2 exhibits strong GTPase-stimulating activity toward Rap1. Rap1GAP2 is highly phosphorylated, and we have identified cGKI as a Rap1GAP2 kinase. cGKI phosphorylates Rap1GAP2 exclusively on serine 7, a residue present only in the platelet splice variants of Rap1GAP2. Phosphorylation of Rap1GAP2 by cGKI might mediate inhibitory effects of NO/cGMP on Rap1. Rap1GAP2 is the first GTPase-activating protein of Rap1 found in platelets and is likely to have an important regulatory role in platelet aggregation.
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Text Mining Data
Rap1 — integrin alpha: "
The Ras-like guanine-nucleotide binding protein
Rap1 controls
integrin alpha ( IIb ) beta3 activity and platelet aggregation
"
Rap1 ⊣ cGMP dependent protein kinase (cGKI): "
Recently, we have found that Rap1 activation can be blocked by the nitric oxide/cyclic guanosine monophosphate ( NO/cGMP ) signaling pathway by type 1 cGMP dependent protein kinase (cGKI)
"
Rap1 → Rap1GAP2: "
Phosphorylation of Rap1GAP2 by cGKI might mediate inhibitory effects of NO/cGMP on Rap1
"
Manually curated Databases
-
Reactome Reaction:
RAP1A
→
SIPA1
(reaction)
-
Reactome Reaction:
RAP1B
→
RAP1GAP
(reaction)
-
Reactome Reaction:
RAP1B
→
RAP1GAP2
(reaction)
-
Reactome Reaction:
RAP1A
→
RAP1GAP2
(reaction)
-
Reactome Reaction:
RAP1B
→
SIPA1
(reaction)
-
Reactome Reaction:
RAP1A
→
RAP1GAP
(reaction)
-
Reactome Reaction:
PRKACG
→
RAP1GAP2
(reaction)
-
Reactome Reaction:
RAP1GAP2
→
PRKG1
(reaction)
-
Reactome Reaction:
PRKACA
→
RAP1GAP2
(reaction)
-
Reactome Reaction:
PRKACB
→
RAP1GAP2
(reaction)
In total, 10 gene pairs are associated to this article in curated databases