[Signal-conducting and low molecular weight GTP-binding proteins from the lung and endothelium: localization in membranes and cytosol, interaction with F-actin].
The following proteins have been identified in mammalian lung and endothelium, using [32P]ADP-ribosylation by bacterial ADP-ribosyltransferase, immuno- and [alpha-32P]GTP-blottings: 41 kDa Gi1 alpha, 40 kDa Gi2 alpha, 41 kDa Gi3 alpha, 40 kDa and 45 kDa subunits of GS alpha, 36 kDa beta 1 and 35 kDa beta 2 subunits of signal-transmitting GTP-binding proteins (G-proteins), the 19-26 kDa low molecular weight GTP-binding proteins (SMG-proteins) ras, rho, rac, G25K (Gp), as well as ARF and SMG proteins binding with a high affinity to [alpha-32P]GTP. These G- and SMG-proteins are contained in various proportions in membrane and cytosol fractions of lung and endothelium cells. Subunits Gi2 alpha and GS alpha (but not beta 1 or SMG-proteins) my partially (approximately 1%) dissociate from the membrane by the action of the GTP analogs GTP[S] or Gpp(NH)p in the presence of magnesium ions. Extraction with low ionic strength buffer solutions in the presence of EDTA is accompanied by the release of G-actin sensitive to whooping cough toxin Gi2 alpha and beta i subunits. The functionally coupled into a alpha beta gamma heterodimer Gi-protein subunits (predominantly Gi2 alpha and beta i) present in the cytosol fraction as well as the SMG-proteins revealed by [alpha-32P]GTP-blotting (but not the SMG-proteins sensitive to the botulinic C3 exoenzyme, rho/rac, or ARF, may interact with F-actin. Approximately 20% of these proteins are associated with the Triton X-100 insoluble (cytoskeletal) fraction of the endothelium. A conclusion is drawn that interactions of G- and SMG-proteins with actin filaments may be the reason for the formation of "multidisperse" structure in a cell.
Panchenko
M P
MP
Starikova
M G
MG
Grishin
A V
AV
Niupenko
E V
EV
Kabaeva
N V
NV
Romanov
Iu A
IuA
Antonov
A S
AS
Tkachuk
V A
VA
D000199:Actins / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D008168:Lung / Q000378:metabolism*; D008970:Molecular Weight; D015398:Signal Transduction; D013552:Swine
D000199:Actins; D019204:GTP-Binding Proteins
Signal-provodiashchie i nizkomolekuliarnye GTP-sviazyvaiushchie belki legkikh i éndoteliia: lokalizatsiia v membranakh i tsitozole, vzaimodeĭstvie s F-aktinom.