HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Schick, P. K. Articles by He, X. L. Search for Related Content PubMed PubMed Citation Articles by Schick, P. K. Articles by He, X. L. Social Bookmarking                      What's this?

Journal of Lipid Research, Vol 31, 1645-1654, Copyright © 1990 by Lipid Research, Inc.

ARTICLES

Composition and synthesis of glycolipids in megakaryocytes and platelets: differences in synthesis in megakaryocytes at different stages of maturation

PK Schick and XL He
Cardeza Foundation for Hematologic Research, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107-5099.

The composition and synthesis of megakaryocyte and platelet glycolipids were compared since these lipids are thought to be important for biologic activities such as adhesion and maturation. Highly purified guinea pig megakaryocytes at different stages of maturation and platelets were studied. Glycolipids and gangliosides were extracted, separated by thin-layer chromatography, and the carbohydrate content was analyzed by gas-liquid chromatography (GLC). Synthesis of ceramides and glycolipids was determined by the incubation of megakaryocytes with [14C]acetate, [3H]palmitic acid, and [3H]galactose. A major neutral glycolipid present in guinea pig megakaryocytes and platelets was identified as asialoGM2 by selective enzymatic hydrolysis with beta-N- acetylhexosaminidase, alpha-galactosidase and endo-beta-galactosidase, and carbohydrate analysis by GLC. Trace amounts of asialoGM1 were detected immunologically. The cells also contained glucosyl ceramide and lactosyl ceramide. Several ganglosides were detected of which one was identified as GM1 by its reaction with the beta-subunit of cholera toxin and by the identification of an asialoGM1 core with anti- asialoGM1 antibody after desialylation. The synthesis of ceramides from palmitic acid and acetate was 5 and 10 times greater, respectively, in megakaryocytes than in platelets. Ceramide and glycolipid synthesis from palmitic acid occurred primarily in immature megakaryocytes while synthesis from acetate occurred primarily in more mature megakaryocytes. The glycosylation of ceramides from galactose was 42 times greater in megakaryocytes than in platelets. Thus, ceramides and glycolipids are primarily synthesized in megakaryocytes, but platelets retain the capacity to synthesize significant amounts of free ceramides. The glycosylation of free ceramides occurs almost exclusively in megakaryocytes and only in trace amounts in platelets. These data indicate that megakaryocytes determine the composition of glycolipids in platelets and that there is considerable compartmentalization of glycolipid synthesis and membrane assembly at various stages of megakaryocytes development.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				P. K. Schick, J. Walker, B. Profeta, L. Denisova, and V. Bennett Synthesis and Secretion of von Willebrand Factor and Fibronectin in Megakaryocytes at Different Phases of Maturation Arterioscler. Thromb. Vasc. Biol., April 1, 1997; 17(4): 797 - 801. [Abstract] [Full Text]