Linked Life Data

17609437

Source:http://linkedlifedata.com/resource/pubmed/id/17609437

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2007-10-1
pubmed:abstractText
The dynamics of glycoprotein hormone alpha-subunit (GPHalpha) maturation and GPHalpha alpha homodimer formation were studied in presence (JEG-3 choriocarcinoma cells) and absence (HeLa cells) of hCGbeta. In both cases, the major initially occurring GPHalpha variant in [35S]Met/Cys-labeled cells carried two N-glycans (M(r app) = 22 kDa). Moreover, a mono-N-glycosylated in vivo association-incompetent GPHalpha variant (M(r app) = 18 kDa) was observed. In JEG-3 cells the early 22-kDa GPHalpha either associated with hCGbeta, or showed self-association to yield GPHalpha alpha homodimers, or was later converted into heavily glycosylated large free GPHalpha (M(r app) = 24 kDa). Micro-preparative isolation of intracellular GPHalpha alpha homodimers of JEG-3 cells and their conversion by reduction revealed that they consisted of 22-kDa GPHalpha monomers and not of large free GPHalpha. In HeLa cells, the large free GPHalpha variant was not observed, whereas GPHalpha alpha homodimers were present. Intracellularly, early GPHalpha alpha homodimers (35 kDa) and late variants (JEG-3: 44 kDa, HeLa: 39 kDa) were found. Both cell types secreted 45 kDa GPHalpha alpha homodimers. Large free GPHalpha and GPHalpha alpha homodimers were more rapidly sialylated than hCG alphabeta-heterodimers indicating a sequestration mechanism in the secretory pathway. In GPHalpha alpha homo- as well as hCG alphabeta-heterodimers the subunit interaction site, located on loop 2 of GPHalpha (amino acids 33-42), became immunologically inaccessible indicating similar spatial orientation of GPHalpha in both types of dimers. The studies demonstrate the formation, in vivo dynamics of GPHalpha alpha homodimers, and the pathways of the cellular metabolism of variants of GPHalpha, monoglycosylated GPHalpha and large free GPHalpha.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0888-8809
pubmed:author
pubmed:issnType
Print
pubmed:volume
21
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2551-64
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Rapid maturation of glycoprotein hormone free alpha-subunit (GPHalpha) and GPHalpha alpha homodimers.
pubmed:affiliation
Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg, Federal Republic of Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't