ISSN:
0021-9541
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
This study has explored the sulfation of proteins by guinea pig megakaryocytes and platelets and by human platelets. Guinea pig megakaryocytes were incubated in vitro with [35S]sulfate, and the sulfated proteins were separated from proteoglycans by DEAE-Sephacel chromatography and analyzed by SDS-PAGE. The megakaryocytes esterified sulfate to a number of proteins, with the most extensive label migrating at Mr 42,000, and a second heavily labeled band at Mr 103,000 in the 0.1 M NaCl DEAE eluate, and 50 and 180 kDa in the 0.23 M NaCl eluate. [35S]-Labeled GPIbα was immunoprecipitated from megakaryocyte Triton X-100 extracts. Guinea pig platelet proteins were labeled in vivo by injection of the animals with a single dose of H235SO4. The platelets were activated with thrombin, and cytoskeletal proteins were isolated after treatment of the activated platelets with Triton X-100. About 20% of the platelet macromolecule-associated [35S]sulfate was incorporated into sulfated proteins, which were recovered primarily in the cytoskeleton. The cytoskeleton-associated sulfate radiolabel migrated on SDS-PAGE primarily with actin and additionally with several higher molecular weight proteins. A Mr 42,000 [35S]-labeled protein was immunoprecipitated by a monoclonal anti-actin antibody, along with molecules of Mr 160,000 and 180,000 and some higher Mr material, from the megakaryocytes labeled in vitro with [35S]sulfate. Actin was labeled on 2D isoelectric focusing/SDS-PAGE gels. In addition, there was a very acidic series of heavily [35S]-labeled 42 kDa proteins with about eight components of different isoelectric points with a pattern identical to the Mr 40,000 cytoskeletal-associated glycoprotein Pltpg40 isolated by Hildreth et al. (1991, Blood 77:121). We hypothesize that sulfation of the cytoskeletal proteins might be involved in cytoskeletal protein interactions and function. © 1994 wiley-Liss, Inc.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1041590219
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