Isolation of GTP-binding proteins from myeloid HL-60 cells. Identification of two pertussis toxin substrates.

Journal Article (Journal Article)

We have isolated the major GTP-binding proteins from myeloid HL-60 cell plasma membranes. Two pertussis toxin substrates with similar apparent molecular masses of 40 and 41 kDa, respectively, are contained in these preparations, with both proteins being ADP-ribosylated to a similar extent. Partial chymotryptic proteolysis of fractions containing the [32P]ADP-ribosylated 40-kDa GTP-binding protein alpha subunit demonstrated production of 32P-labeled peptides of 28 and 16 kDa which were not observed after partial proteolysis of fractions containing solely the 41-kDa protein. Similarly, mild acid hydrolysis produced an additional 28-kDa fragment only from fractions containing the 40-kDa protein. The results presented here indicate the presence of two distinct pertussis toxin substrates in myeloid cells. The 41-kDa pertussis toxin substrate is likely to represent the alpha subunit of the inhibitory GTP-binding regulatory protein of adenylate cyclase, whereas the 40-kDa substrate may represent the alpha subunit of the GTP-binding protein which is coupled to chemoattractant receptors. In addition to the pertussis toxin substrates, an additional major peak of guanosine 5'-(3-O-thio)triphosphate-binding activity closely corresponded to the appearance of a 23-kDa protein.

Full Text

Duke Authors

Cited Authors

  • Uhing, RJ; Polakis, PG; Snyderman, R

Published Date

  • November 15, 1987

Published In

Volume / Issue

  • 262 / 32

Start / End Page

  • 15575 - 15579

PubMed ID

  • 3119579

International Standard Serial Number (ISSN)

  • 0021-9258


  • eng

Conference Location

  • United States