These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: The coated vesicle vacuolar (H+)-ATPase associates with and is phosphorylated by the 50-kDa polypeptide of the clathrin assembly protein AP-2.
    Author: Myers M, Forgac M.
    Journal: J Biol Chem; 1993 May 05; 268(13):9184-6. PubMed ID: 8486617.
    Abstract:
    We have previously noted a 50-kDa polypeptide (p50) co-purifying with preparations of the bovine brain clathrin-coated vesicle vacuolar (H+)-ATPase (V-ATPase) (Zhang, J., Myers, M., and Forgac, M. (1992) J. Biol. Chem. 267, 9773-9778). We show that p50 is also immunoprecipitated with the V-ATPase, further suggesting its specific association with the proton pump. To determine the identity of this 50-kDa polypeptide and the stoichiometry of its association with the V-ATPase, we performed N-terminal amino acid sequencing and quantitative amino acid analysis of the gel-purified protein. These results revealed the unknown polypeptide to be the 50-kDa subunit of the clathrin assembly protein AP-2 (AP50); we estimate the stoichiometry of association is one AP50 per V-ATPase complex. AP50 is an N-ethylmaleimide (NEM)-inhibitable autokinase and incubation of purified V-ATPase with [gamma-32P]ATP resulted in the NEM-sensitive phosphorylation of AP50 and the B subunit of the V-ATPase. The same phosphorylation pattern is seen if the labeling reaction is done with intact clathrin-coated vesicles and the V-ATPase subsequently immunoprecipitated from the solubilized vesicles. This represents the first report of phosphorylation of one of the V-ATPase subunits. The functional significance of this phosphorylation for regulation or targeting of the V-ATPase in vivo remains to be determined.
    [Abstract] [Full Text] [Related] [New Search]