RhoH GTPase: a key regulator of hematopoietic cell proliferation and apoptosis?
Rho GTPases are well characterized as critical regulators of cell growth and actin cytoskeleton in eukaryotic cells. The RhoE/Rnd3 subfamily member RhoH is hematopoietic- specific and GTPase deficient and thus is expected to be in the constitutively active, GTP-bound conformation. The activity of RhoH is likely regulated by the level of expression rather than GTP-binding/GTP-hydrolysis cycle in the cell. By RNAi based knock-down and overexpression approaches we recently have shown in hematopoietic progenitor cells that RhoH negatively impacts on growth factor-induced proliferation and survival and modulates chemokine-induced actin reorganization and cell migration. In addition, RhoH appears to counteract Rac GTPase activities, suggesting a possible mechanism by which RhoH functions as an antagonist of Rac signaling in the regulation of cell growth and actin-based functions in blood lineages.
Gu
Yi
Y
Division of Experimental Hematology, Cincinnati Children's Hospital Research Foundation, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA. Yi.Gu@cchmc.org
Zheng
Yi
Y
Williams
David A
DA
D000199:Actins / Q000032:analysis / Q000502:physiology; D000818:Animals; D017209:Apoptosis; D002465:Cell Movement; D049109:Cell Proliferation; D003599:Cytoskeleton / Q000737:chemistry / Q000502:physiology; D005786:Gene Expression Regulation; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000502:physiology*; D006801:Humans; D051379:Mice; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D020744:rac GTP-Binding Proteins / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
D000199:Actins; C447841:RhoH protein, human; C496930:RhoH protein, mouse; D014157:Transcription Factors; D020744:rac GTP-Binding Proteins; D020741:rho GTP-Binding Proteins