Role of RGS proteins in regulating the migration of B lymphocytes.
The migration of B lymphocytes into distinct microenvironments in secondary lymphoid tissues and maintenance of cells in these micro-domains is strictly structured and likely supports the proper regulation of immune responses to both foreign and self-antigens. Chemokines' and other chemoattactants' signals serve as signposts to direct cell migration. They signal cells through heptahelical receptors, which couple to heterotrimeric G proteins (G protein-coupled receptors or GPCRs). The regulation of the signals transduced through these receptors ultimately determines the positioning of cells in lymphoid tissues. A variety of mechanisms regulate GPCR signaling including a family of approximately 25 proteins termed regulators of G protein signaling (RGS). These proteins act as GTPase activating proteins for G alpha subunits and can also function as effector antagonists of specific G alpha subunits, thereby attenuating signaling through GPCRs such as chemokine receptors. RGS proteins possess some degree of receptor and G alpha subunit specificity. Thus, the particular spectrum of RGS proteins and their expression levels within a cell will determine the duration and magnitude of G protein signaling initiated by chemokines. In this review we illustrate the role RGS proteins have in regulating B cell signaling responses to chemoattractant stimuli during homeostasis as well as during an immune response.
Moratz
Chantal
C
Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20891, USA.
Harrison
Kathleen
K
Kehrl
John H
JH
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D002465:Cell Movement / Q000276:immunology / Q000502:physiology*; D018925:Chemokines / Q000276:immunology / Q000378:metabolism*; D020690:GTPase-Activating Proteins / Q000276:immunology / Q000378:metabolism; D006801:Humans; D011485:Protein Binding / Q000276:immunology; D020710:RGS Proteins / Q000276:immunology / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*
D018925:Chemokines; D020690:GTPase-Activating Proteins; D020710:RGS Proteins; D043562:Receptors, G-Protein-Coupled