Characteristics of the regulation of the process of protein phosphorylation on tumor cell membranes

: The regulation mechanism of intracellular protein concentrations which are phosphorylated by membrane-bound protein kinases is considered. It is shown that cells depending on intracellular parameters may be in two alternative states which are characterized either by the absence (or very low concentration) or the presence of phosphorylated proteins, that provides their different sensitivity to the growth factors. A conclusion is drawn on the possibility of existence of transformed cells which sensitivity to growth factors is inhibited.