Format

Send to

Choose Destination
Am J Respir Cell Mol Biol. 2001 Aug;25(2):156-63.

The juxtamembrane lysine and arginine residues of surfactant protein C precursor influence palmitoylation via effects on trafficking.

Author information

1
Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, The Netherlands. A.tenBrinke@vet.uu.nl

Abstract

Surfactant protein (SP)-C propeptide (proSP-C) becomes palmitoylated on cysteines 5 and 6 before mature SP-C is formed by several proteolytic steps. To study the structural requirements for the palmitoylation of proSP-C, his-tagged human proSP-C (his-proSP-C) and his-proSP-C mutants were expressed in Chinese hamster ovary cells and analyzed by metabolic labeling with [(3)H]palmitate and immunocytochemistry. Substitution of cysteines 5 and 6 by serines showed that these were the only two cysteine residues palmitoylated in his-proSP-C. Substitution of the juxtamembrane basic residues lysine and arginine by uncharged glutamines led to a large decrease in palmitoylation level of proSP-C. The addition of brefeldin A nearly abolished this decrease for the lysine and double mutant; the palmitoylation of the arginine mutant increased also, but not to wild-type (WT) levels. Fluorescence immunocytochemistry showed that WT proSP-C was localized in punctate vesicles throughout the cell, whereas the mutant lacking the juxtamembrane positive charges was found more perinuclear, probably in the endoplasmic reticulum (ER). This indicates that the two basic juxtamembrane residues influence palmitoylation of proSP-C by preventing the transport of proSP-C out of the ER, implying that proSP-C becomes palmitoylated normally in a compartment distal to the ER.

PMID:
11509324
DOI:
10.1165/ajrcmb.25.2.4423
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Atypon
Loading ...
Support Center