Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
27
pubmed:dateCreated
2011-7-4
pubmed:abstractText
Adult hematopoietic progenitor cells (HPCs) are maintained by highly coordinated signals in the bone marrow. The molecular mechanisms linking intracellular signaling network of HPCs with their microenvironment remain poorly defined. The Rho family GTPase Rac1/Rac2 has previously been implicated in cell functions involved in HPC maintenance, including adhesion, migration, homing, and mobilization. In the present studies we have identified R-Ras, a member of the Ras family, as a key signal mediator required for Rac1/Rac2 activation. We found that whereas Rac1 activity is up-regulated upon stem cell factor, integrin, or CXCL12 stimulation, R-Ras activity is inversely up-regulated. Expression of a constitutively active R-Ras mutant resulted in down-regulation of Rac1-activity whereas deletion of R-Ras led to an increase in Rac1/Rac2 activity and signaling. R-Ras(-/-) HPCs displayed a constitutively assembled cortical actin structure and showed increased directional migration. Rac1/Rac2 inhibition reversed the migration phenotype of R-Ras(-/-) HPCs, similar to that by expressing an R-Ras active mutant. Furthermore, R-Ras(-/-) mice showed enhanced responsiveness to G-CSF for HPC mobilization and exhibited decreased bone marrow homing. Transplantation experiments indicate that the R-Ras deficiency-induced HPC mobilization is a HPC intrinsic property. These results indicate that R-Ras is a critical regulator of Rac signaling required for HPC migration, homing, and mobilization.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1083-351X
pubmed:author
pubmed:issnType
Electronic
pubmed:day
8
pubmed:volume
286
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
24068-78
pubmed:meshHeading
pubmed-meshheading:21572048-Actins, pubmed-meshheading:21572048-Adult Stem Cells, pubmed-meshheading:21572048-Animals, pubmed-meshheading:21572048-Cell Movement, pubmed-meshheading:21572048-Enzyme Activation, pubmed-meshheading:21572048-Gene Expression Regulation, Enzymologic, pubmed-meshheading:21572048-Hematopoietic Stem Cell Mobilization, pubmed-meshheading:21572048-Hematopoietic Stem Cell Transplantation, pubmed-meshheading:21572048-Hematopoietic Stem Cells, pubmed-meshheading:21572048-Mice, pubmed-meshheading:21572048-Mice, Knockout, pubmed-meshheading:21572048-Mutation, pubmed-meshheading:21572048-Neuropeptides, pubmed-meshheading:21572048-Signal Transduction, pubmed-meshheading:21572048-Transplantation, Homologous, pubmed-meshheading:21572048-Up-Regulation, pubmed-meshheading:21572048-rac GTP-Binding Proteins, pubmed-meshheading:21572048-ras Proteins
pubmed:year
2011
pubmed:articleTitle
R-Ras and Rac GTPase cross-talk regulates hematopoietic progenitor cell migration, homing, and mobilization.
pubmed:affiliation
Division of Experimental Hematology and Cancer Biology, Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio 45229, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural