Induction of phosphorylation of dolichol during embryonic development of the sea urchin.

Abstract

ence of compactin, which blocks de novo synthesis of dolichol, the labeling of dolichyl [32P]monophosphate was still 25% of control values. This finding suggested the possibility that endogenous, reserve pools of preformed dolichol were being phosphorylated. To study this possibility membrane preparations were prepared from embryos at various stages of development. In vitro experiments utilizing these membranes and [y-”P] CTP revealed the presence of a dolichol kinase that catalyzes formation of dolichyl [32P]monophosphate from both endogenous and exogenous dolichol. Enzymological studies provided information on a number of properties of this enzyme, and showed that under conditions of saturating substrate concentrations the level of the enzyme increased at least 3.5- to 4.0-fold over the course of development to the mesenchyme blastula stage. At later stages of development the kinase activity decreased to very low levels. These results indicate that both de nouo synthesis of dolichol, as well as its phosphorylation, may play an important role in the observed increase in glycoprotein synthesis prior to gastrulation. The possible role of dolichol kinase in the activation of stored dolichol, and perhaps in the pathway for its de novo biosynthesis in this and other biological systems, is discussed.