Linked Life Data

14559916

Source:http://linkedlifedata.com/resource/pubmed/id/14559916

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
51
pubmed:dateCreated
2003-12-15
pubmed:abstractText
Type I signal peptidases (SPs) comprise a family of structurally related enzymes that cleave signal peptides from precursor proteins following their transport out of the cytoplasmic space in eukaryotic and prokaryotic cells. One such enzyme, the mitochondrial inner membrane peptidase, has two catalytic subunits, which recognize distinct cleavage site motifs in their signal peptide substrates. The only other known type I SP with two catalytic subunits is the signal peptidase complex (SPC) in the mammalian endoplasmic reticulum. Here, we tested the hypothesis that, as with inner membrane peptidase catalytic subunits, SPC catalytic subunits exhibit nonoverlapping substrate specificity. We constructed two yeast strains without endogenous SP, one expressing canine SPC18 and the other expressing a truncation of canine SPC21 (SPC21 Delta N), which lacks 24 N-terminal residues that prevent expression of SPC21 in yeast. By monitoring a variety of soluble and membrane-bound substrates, we find that, in contrast to the tested hypothesis, SPC catalytic subunits exhibit overlapping substrate specificity. SPC18 and SPC21 Delta N do, however, cleave some substrates with different efficiencies, although no pattern for this behavior could be discerned. In light of the functional similarities between SPC proteins, we developed a membrane protein fragmentation assay to monitor the position of the catalytic sites relative to the surface of the endoplasmic reticulum membrane. Using this assay, our results suggest that the active sites of SPC18 and SPC21 Delta N are located 4-11 A above the membrane surface. These data, thus, support a model that SPC18 and SPC21 are functionally and structurally similar to each other.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
278
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
50932-9
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:14559916-Amino Acid Sequence, pubmed-meshheading:14559916-Animals, pubmed-meshheading:14559916-Catalytic Domain, pubmed-meshheading:14559916-DNA, Complementary, pubmed-meshheading:14559916-Dogs, pubmed-meshheading:14559916-Endoplasmic Reticulum, pubmed-meshheading:14559916-Genetic Complementation Test, pubmed-meshheading:14559916-Mannosyltransferases, pubmed-meshheading:14559916-Membrane Proteins, pubmed-meshheading:14559916-Molecular Sequence Data, pubmed-meshheading:14559916-Mutation, pubmed-meshheading:14559916-Peptide Fragments, pubmed-meshheading:14559916-Protein Subunits, pubmed-meshheading:14559916-Saccharomyces cerevisiae Proteins, pubmed-meshheading:14559916-Sequence Alignment, pubmed-meshheading:14559916-Serine Endopeptidases, pubmed-meshheading:14559916-Substrate Specificity, pubmed-meshheading:14559916-Transfection, pubmed-meshheading:14559916-Yeasts
pubmed:year
2003
pubmed:articleTitle
Genetic complementation in yeast reveals functional similarities between the catalytic subunits of mammalian signal peptidase complex.
pubmed:affiliation
Department of Microbiology and Immunology, School of Medicine, Vanderbilt University, Nashville, Tennessee 37232-2363, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't