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The membrane spanning domain of beta‐1,4‐galactosyltransferase specifies trans Golgi localization.
Author(s) -
Nilsson T.,
Lucocq J.M.,
Mackay D.,
Warren G.
Publication year - 1991
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1991.tb04923.x
Subject(s) - biology , golgi apparatus , galactosyltransferase , cytoplasm , microbiology and biotechnology , biochemistry , enzyme , endoplasmic reticulum
Chimeric cDNAs were constructed so as to generate hybrid proteins in which different parts of the N‐terminal domain of the human invariant chain were replaced by equivalent sequences from the trans Golgi resident enzyme, beta‐1,4‐galactosyltransferase. The cytoplasmic and membrane spanning domains of galactosyltransferase were found to be sufficient to retain all of the hybrid invariant chain in trans Golgi cisternae as judged by indirect immunofluorescence, treatment with brefeldin A and immuno‐electron microscopy. As few as ten amino acids corresponding to the lumenal half of the membrane spanning domain of the Golgi enzyme sufficed to localize most of the hybrid invariant chain to the trans cisternae. A cytoplasmic domain was necessary for complete retention as assessed by flow cytofluorometry but could be provided either by galactosyltransferase or by invariant chain. This suggests that the cytoplasmic domain plays a role accessory to the membrane spanning domain, the latter mediating compartmental specificity.