Linked Life Data

8663411

Source:http://linkedlifedata.com/resource/pubmed/id/8663411

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
29
pubmed:dateCreated
1996-9-12
pubmed:abstractText
We have investigated the trafficking of integral membrane peptidylglycine alpha-amidating monooxygenase (PAM) in the neuroendocrine AtT-20 cell line. This bifunctional enzyme has two domains which together catalyze the COOH-terminal alpha-amidation of peptidylglycine substrates yielding amidated products stored in secretory granules. As soluble proteins, both catalytic domains were independently targeted to secretory granules. In contrast, membrane PAM was largely localized to the trans-Golgi network (TGN). Upon truncation of its cytoplasmic COOH-terminal domain, membrane PAM was less efficiently cleaved by secretory granule enzymes and accumulated on the plasma membrane. When transferred to the lumenal domain of the interleukin 2 receptor alpha-chain (Tac protein), the cytoplasmic domain of PAM caused rerouting of Tac from the surface to the TGN and supported internalization of Tac antibody from the plasma membrane. To define sequences in the cytoplasmic domain of integral membrane PAM involved in its trafficking, we expressed PAM proteins containing truncations, deletions, or point mutations in the COOH-terminal cytoplasmic domain. PAM proteins were not retained in the TGN when half of the cytoplasmic domain was deleted; such proteins accumulated on the plasma membrane, were not efficiently internalized, and were cleaved to generate a bifunctional PAM protein that was not stored in secretory granules. A tyrosine-based internalization motif was identified, which was not required for efficient cleavage of full-length integral membrane PAM by secretory granule enzymes. Deletion of an 18-amino acid domain surrounding this Tyr residue both diminished cleavage of membrane PAM by secretory granule enzymes and eliminated internalization of PAM from the plasma membrane. The cytoplasmic domain is responsible for retaining membrane PAM in the TGN and for retrieving membrane PAM from the cell surface, while the lumenal catalytic domains of PAM appear to be responsible for targeting the protein to secretory granules.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
271
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
17526-35
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:8663411-Amino Acid Sequence, pubmed-meshheading:8663411-Animals, pubmed-meshheading:8663411-Cell Line, pubmed-meshheading:8663411-Cytoplasmic Granules, pubmed-meshheading:8663411-Cytosol, pubmed-meshheading:8663411-Endopeptidases, pubmed-meshheading:8663411-Golgi Apparatus, pubmed-meshheading:8663411-Intracellular Membranes, pubmed-meshheading:8663411-Mixed Function Oxygenases, pubmed-meshheading:8663411-Models, Biological, pubmed-meshheading:8663411-Molecular Sequence Data, pubmed-meshheading:8663411-Multienzyme Complexes, pubmed-meshheading:8663411-Mutagenesis, Site-Directed, pubmed-meshheading:8663411-Point Mutation, pubmed-meshheading:8663411-Polymerase Chain Reaction, pubmed-meshheading:8663411-Protein Processing, Post-Translational, pubmed-meshheading:8663411-Recombinant Fusion Proteins, pubmed-meshheading:8663411-Recombinant Proteins, pubmed-meshheading:8663411-Sequence Deletion, pubmed-meshheading:8663411-Signal Transduction, pubmed-meshheading:8663411-Transfection
pubmed:year
1996
pubmed:articleTitle
Identification of routing determinants in the cytosolic domain of a secretory granule-associated integral membrane protein.
pubmed:affiliation
Physiology Department, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.