Targeting of a lysosomal membrane protein: a tyrosine-containing endocytosis signal in the cytoplasmic tail of lysosomal acid phosphatase is necessary and sufficient for targeting to lysosomes.
Lysosomal acid phosphatase (LAP) is synthesized as a transmembrane protein with a short carboxy-terminal cytoplasmic tail of 19 amino acids, and processed to a soluble protein after transport to lysosomes. Deletion of the membrane spanning domain and the cytoplasmic tail converts LAP to a secretory protein, while deletion of the cytoplasmic tail as well as substitution of tyrosine 413 within the cytoplasmic tail against phenylalanine causes accumulation at the cell surface. A chimeric polypeptide, in which the cytoplasmic tail of LAP was fused to the ectoplasmic and transmembrane domain of hemagglutinin is rapidly internalized and tyrosine 413 of the LAP tail is essential for internalization of the fusion protein. A chimeric polypeptide, in which the membrane spanning domain and cytoplasmic tail of LAP are fused to the ectoplasmic domain of the Mr 46 kd mannose 6-phosphate receptor, is rapidly transported to lysosomes, whereas wild type receptor is not transported to lysosomes. We conclude that a tyrosine containing endocytosis signal in the cytoplasmic tail of LAP is necessary and sufficient for targeting to lysosomes.
Georg-August-Universität Göttingen, Abt. Biochemie II, FRG.
C
C
Peters
M
M
Braun
B
B
Weber
M
M
Wendland
B
B
Schmidt
R
R
Pohlmann
A
A
Waheed
K
K
von Figura
D000135:Acid Phosphatase / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D002451:Cell Compartmentation; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D006224:Cricetinae; D004705:Endocytosis; D005455:Fluorescent Antibody Technique; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000378:metabolism*; D007668:Kidney; D008247:Lysosomes / Q000201:enzymology / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D011498:Protein Precursors / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013329:Structure-Activity Relationship; D014443:Tyrosine
D008562:Membrane Glycoproteins; D011498:Protein Precursors; D011993:Recombinant Fusion Proteins; D014443:Tyrosine; D000135:Acid Phosphatase