The membrane-spanning segment of invariant chain (Iγ) contains a potentially cleavable signal sequence

Abstract

The human invariant chain (I gamma) of class II histocompatibility antigens spans the membrane of the endoplasmic reticulum once. It exposes a small amino-terminal domain on the cytoplasmic side and a carboxy-terminal, glycosylated domain on the exoplasmic side of the membrane. When the exoplasmic domain of I gamma is replaced by the cytoplasmic protein chloramphenicol acetyltransferase (CAT), CAT becomes the exoplasmic, glycosylated domain of the resulting membrane protein I gamma CAT. Deletion of the hydrophilic cytoplasmic domain from I gamma CAT gives rise to a secreted protein from which an amino-terminal segment is cleaved, most likely by signal peptidase. We conclude that the membrane-spanning region of I gamma contains a signal sequence in its amino-terminal half and that hydrophilic residues at the amino-terminal end of a signal sequence can determine cleavage by signal peptidase.

Multiple topogenic sequences determine the transmembrane orientation of the hepatitis B surface antigen.

“…7,1987 on 3) or mock digested (lane 1) with 0.6 mg of trypsin (Boehringer) per ml for 1 h at 25°C in manner similar to that described in Table 1 unable to separate the translocation signal from that required for membrane insertion; additional fusions with endpoints within this region will be required to determine whether these functions can be physically uncoupled. In most respects, signal II resembles the internal elements of so-called type II membrane proteins, such as the transferrin and asialoglycoprotein receptors (15,29,41), which similarly translocate C-terminal-flanking domains while conferring on the protein a transmembrane orientation (N-terminus cytoplasmic, C-terminus lumenal). That this is also the orientation conferred by signal II is indicated by the phenotype of numerous mutants.…”

Transport to the cell surface of a peptide sequence attached to the truncated C terminus of an N-terminally anchored integral membrane protein.

“…The fusion protein containing Fl ATPase P subunit attached to P-galactosidase also appeared to be correctly localized in the mitochondrion although it conferred an ATPase-negative phenotype to cells that expressed the hybrid protein (9). In another instance, when a hybrid protein was constructed in which the exoplasmic domain of the invariant chain (1ly; 20) was replaced by procaryotic chloramphenicol acetyltransferase, the latter was found to be exoplasmic and glycosylated (20).…”

Long-lived Signal Peptide of Lymphocytic Choriomeningitis Virus Glycoprotein pGP-C

“…KL25 is a mouse monoclonal antibody reactive with the LCMV glycoprotein GP-1 (31 Cells were harvested and lysed for 15 min on ice in 100 mM NaCl, 20 mM HEPES/KOH (pH 7.3), 5 mM MgCl 2 , 1% (w/v) Triton X-100, 100 g/ml phenylmethylsulfonyl fluoride, 10 g/ml aprotinin, 10 g/ml leupeptin, and 10 g/ml pepstatin. Equal aliquots were used for immunoprecipitation (34).…”