TY - JOUR
T1 - Mechanisms Governing Subcellular Localization and Function of Human RGS2
AU - Heximer, Scott P.
AU - Lim, Han
AU - Bernard, Jennifer L.
AU - Blumer, Kendall J.
PY - 2001/4/27
Y1 - 2001/4/27
N2 - RGS proteins negatively regulate heterotrimeric G proteins at the plasma membrane. RGS2-GFP localizes to the nucleus, plasma membrane, and cytoplasm of HEK293 cells. Expression of activated Gq increased RGS2 association with the plasma membrane and decreased accumulation in the nucleus, suggesting that signal-induced redistribution may regulate RGS2 function. Thus, we identified and characterized a conserved N-terminal domain in RGS2 that is necessary and sufficient for plasma membrane localization. Mutational and biophysical analyses indicated that this domain is an amphipathic α-helix that binds vesicles containing acidic phospholipids. However, the plasma membrane targeting function of the amphipathic helical domain did not appear to be essential for RGS2 to attenuate signaling by activated Gq. Nevertheless, truncation mutants indicated that the N terminus is essential, potentially serving as a scaffold that binds receptors, signaling proteins, or nuclear components. Indeed, the RGS2 N terminus directs nuclear accumulation of GFP. Although RGS2 possesses a nuclear targeting motif, it lacks a nuclear import signal and enters the nucleus by passive diffusion. Nuclear accumulation of RGS2 does not limit its ability to attenuate Gq signaling, because excluding RGS2 from the nucleus was without effect. RGS2 may nonetheless regulate signaling or other processes in the nucleus.
AB - RGS proteins negatively regulate heterotrimeric G proteins at the plasma membrane. RGS2-GFP localizes to the nucleus, plasma membrane, and cytoplasm of HEK293 cells. Expression of activated Gq increased RGS2 association with the plasma membrane and decreased accumulation in the nucleus, suggesting that signal-induced redistribution may regulate RGS2 function. Thus, we identified and characterized a conserved N-terminal domain in RGS2 that is necessary and sufficient for plasma membrane localization. Mutational and biophysical analyses indicated that this domain is an amphipathic α-helix that binds vesicles containing acidic phospholipids. However, the plasma membrane targeting function of the amphipathic helical domain did not appear to be essential for RGS2 to attenuate signaling by activated Gq. Nevertheless, truncation mutants indicated that the N terminus is essential, potentially serving as a scaffold that binds receptors, signaling proteins, or nuclear components. Indeed, the RGS2 N terminus directs nuclear accumulation of GFP. Although RGS2 possesses a nuclear targeting motif, it lacks a nuclear import signal and enters the nucleus by passive diffusion. Nuclear accumulation of RGS2 does not limit its ability to attenuate Gq signaling, because excluding RGS2 from the nucleus was without effect. RGS2 may nonetheless regulate signaling or other processes in the nucleus.
UR - http://www.scopus.com/inward/record.url?scp=0035957996&partnerID=8YFLogxK
U2 - 10.1074/jbc.M009942200
DO - 10.1074/jbc.M009942200
M3 - Article
C2 - 11278586
AN - SCOPUS:0035957996
VL - 276
SP - 14195
EP - 14203
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 17
ER -