Rab1 GTPase promotes expression of beta-adrenergic receptors in rat pulmonary microvascular endothelial cells.
It is known that Rab1 regulates the expression and function of beta-adrenoceptors (beta-ARs) in many cells. However, the effect of these changes in rat pulmonary microvascular endothelial cells (RPMVECs) is not known. In the present study, we investigated the role of Rab1, a Ras-like GTPase that coordinates protein transport from the endoplasmic reticulum (ER) to the Golgi body and regulates the cell-surface targeting and function of endogenous beta-ARs in RPMVECs in the presence of lipopolysaccharide (LPS). We found that lentivirus-driven expression of wild-type Rab1 (Rab1WT) in RPMVECs strongly enhanced the amount of beta-ARs on the cell surface, whereas the dominant-negative mutant Rab1N124I significantly attenuated beta-ARs expression on the cell surface. In addition, LPS stimulation significantly reduced beta-ARs expression on the cell surface in RPMVECs; however, this effect was reversed by over-expression of wild-type Rab1WT. Fluorescent microscopy analysis demonstrated that expression of Rab1N124I and Rab1 small interfering RNA (siRNA) significantly induced the accumulation of green fluorescent protein (GFP)-tagged beta(2)-AR in the ER. Consistent with their effects on beta-ARs export, Rab1WT and Rab1N124I differentially modified the beta-AR-mediated activation of extracellular signal-regulated kinase1/2 (ERK1/2). Importantly, over-expression of Rab1WT markedly reduced LPS-induced hyper-permeability of RPMVECs by increasing the expression of beta(2)-AR on the cell surface. These data reveal that beta-ARs function in RPMVECs could be modulated by manipulating beta-ARs traffic from the ER to the Golgi body. We propose the ER-to-Golgi transport as a regulatory site for control of permeability of RPMVECs.
Li
Yuncheng
Y
Institute of Respiratory Diseases, the Second Affiliated Hospital of the Third Military Medical University, Chongqing 400037, PR China.
Wang
Guansong
G
Institute of Respiratory Diseases, the Second Affiliated Hospital of the Third Military Medical University, Chongqing 400037, PR China.
Lin
Kexiong
K
Institute of Respiratory Diseases, the Second Affiliated Hospital of the Third Military Medical University, Chongqing 400037, PR China.
Yin
Hongjin
H
Institute of Respiratory Diseases, the Second Affiliated Hospital of the Third Military Medical University, Chongqing 400037, PR China.
Zhou
Changxi
C
Institute of Respiratory Diseases, the Second Affiliated Hospital of the Third Military Medical University, Chongqing 400037, PR China.
Liu
Ting
T
Institute of Respiratory Diseases, the Second Affiliated Hospital of the Third Military Medical University, Chongqing 400037, PR China.
Wu
Guangyu
G
Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences center, New Orleans., LA 70112, United States.
Qian
Guisheng
G
Institute of Respiratory Diseases, the Second Affiliated Hospital of the Third Military Medical University, Chongqing 400037, PR China.
D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D018014:Gene Transfer Techniques; D016086:Lentivirus / Q000235:genetics; D008024:Ligands; D008070:Lipopolysaccharides / Q000494:pharmacology; D008168:Lung / Q000098:blood supply* / Q000166:cytology*; D055806:Microvessels / Q000166:cytology*; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D018342:Receptors, Adrenergic, beta-1 / Q000378:metabolism*; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D020761:rab1 GTP-Binding Proteins / Q000378:metabolism*
D008024:Ligands; D008070:Lipopolysaccharides; D018342:Receptors, Adrenergic, beta-1; D018343:Receptors, Adrenergic, beta-2; D048049:Extracellular Signal-Regulated MAP Kinases; D020761:rab1 GTP-Binding Proteins