title: Protein Kinase A (PKA) Type I Interacts with P-Rex1, a Rac Guanine Nucleotide Exchange Factor: EFFECT ON PKA LOCALIZATION AND P-Rex1 SIGNALING.
abstract: Morphology of migrating cells is regulated by Rho GTPases and fine-tuned by protein interactions and phosphorylation. PKA affects cell migration potentially through spatiotemporal interactions with regulators of Rho GTPases. Here we show that the endogenous regulatory (R) subunit of type I PKA interacts with P-Rex1, a Rac guanine nucleotide exchange factor that integrates chemotactic signals. Type I PKA holoenzyme interacts with P-Rex1 PDZ domains via the CNB B domain of RIα, which when expressed by itself facilitates endothelial cell migration. P-Rex1 activation localizes PKA to the cell periphery, whereas stimulation of PKA phosphorylates P-Rex1 and prevents its activation in cells responding to SDF-1 (stromal cell-derived factor 1). The P-Rex1 DEP1 domain is phosphorylated at Ser-436, which inhibits the DH-PH catalytic cassette by direct interaction. In addition, the P-Rex1 C terminus is indirectly targeted by PKA, promoting inhibitory interactions independently of the DEP1-PDZ2 region. A P-Rex1 S436A mutant construct shows increased RacGEF activity and prevents the inhibitory effect of forskolin on sphingosine 1-phosphate-dependent endothelial cell migration. Altogether, these results support the idea that P-Rex1 contributes to the spatiotemporal localization of type I PKA, which tightly regulates this guanine exchange factor by a multistep mechanism, initiated by interaction with the PDZ domains of P-Rex1 followed by direct phosphorylation at the first DEP domain and putatively indirect regulation of the C terminus, thus promoting inhibitory intramolecular interactions. This reciprocal regulation between PKA and P-Rex1 might represent a key node of integration by which chemotactic signaling is fine-tuned by PKA.
authors.affiliation: From the Departments of Pharmacology and.
authors.forename: Lydia
authors.initials: L
authors.lastname: Chávez-Vargas
authors.affiliation: Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, 07360 Mexico.
authors.forename: Sendi Rafael
authors.initials: SR
authors.lastname: Adame-García
authors.affiliation: From the Departments of Pharmacology and.
authors.forename: Rodolfo Daniel
authors.initials: RD
authors.lastname: Cervantes-Villagrana
authors.affiliation: Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, 07360 Mexico.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Castillo-Kauil
authors.affiliation: Departments of Chemistry and Biochemistry and.
authors.forename: Jessica G H
authors.initials: JG
authors.lastname: Bruystens
authors.affiliation: Department of Cell Biology, National Cerebral and Cardiovascular Center Research Institute (NCVC), Osaka, 565-8565 Japan, and.
authors.forename: Shigetomo
authors.initials: S
authors.lastname: Fukuhara
authors.affiliation: Departments of Chemistry and Biochemistry and Pharmacology, University of California San Diego, La Jolla, California 92093.
authors.forename: Susan S
authors.initials: SS
authors.lastname: Taylor
authors.affiliation: Department of Cell Biology, National Cerebral and Cardiovascular Center Research Institute (NCVC), Osaka, 565-8565 Japan, and.
authors.forename: Naoki
authors.initials: N
authors.lastname: Mochizuki
authors.affiliation: Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, 07360 Mexico.
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Reyes-Cruz
authors.affiliation: From the Departments of Pharmacology and jvazquez@cinvestav.mx.
authors.forename: José
authors.initials: J
authors.lastname: Vázquez-Prado
mesh_terms: D002462:Cell Membrane / Q000201:enzymology; D002465:Cell Movement; D054377:Chemokine CXCL12 / Q000502:physiology; D054751:Cyclic AMP-Dependent Protein Kinase Catalytic Subunits / Q000737:chemistry / Q000378:metabolism; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit / Q000737:chemistry / Q000378:metabolism*; D042783:Endothelial Cells / Q000502:physiology; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D010766:Phosphorylation; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D015398:Signal Transduction; D020798:Two-Hybrid System Techniques
chemical_list: C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; D020662:Guanine Nucleotide Exchange Factors; C453280:PREX1 protein, human; C517834:PRKAR1A protein, human; D054751:Cyclic AMP-Dependent Protein Kinase Catalytic Subunits; C517757:PRKACA protein, human
keywords: PDZ domain; Rac (Rac GTPase); guanine nucleotide exchange factor (GEF); protein kinase; protein kinase A (PKA); signal transduction