TY - JOUR
T1 - Cytoskeletal association is important for differential targeting of glucose transporter isoforms in Leishmania
AU - Snapp, Erik L.
AU - Landfear, Scott M.
PY - 1997/12/29
Y1 - 1997/12/29
N2 - The major glucose transporter of the parasitic protozoan Leishmania enriettii exists in two isoforms, one of which (iso-1) localizes to the flagellar membrane, while the other (iso-2) localizes to the plasma membrane of the cell body, the pellicular membrane. These two isoforms differ only in their cytosolic NH2-terminal domains. Using immunoblots and immunofluorescence microscopy of detergent-extracted cytoskeletons, we have demonstrated that iso-2 associates with the microtubular cytoskeleton that underlies the cell body membrane, whereas the flagellar membrane isoform iso- 1 does not associate with the cytoskeleton. Deletion mutants that remove the first 25 or more amino acids from iso-1 are retargeted from the flagellum to the pellicular membrane, suggesting that these deletions remove a signal required for flagellar targeting. Unlike the full-length iso-1 protein, these deletion mutants associate with the cytoskeleton. Our results suggest that cytoskeletal binding serves as an anchor to localize the iso-2 transporter within the pellicular membrane, and that the flagellar targeting signal of iso-1 diverts this transporter into the flagellar membrane and away from the pellicular microtubules.
AB - The major glucose transporter of the parasitic protozoan Leishmania enriettii exists in two isoforms, one of which (iso-1) localizes to the flagellar membrane, while the other (iso-2) localizes to the plasma membrane of the cell body, the pellicular membrane. These two isoforms differ only in their cytosolic NH2-terminal domains. Using immunoblots and immunofluorescence microscopy of detergent-extracted cytoskeletons, we have demonstrated that iso-2 associates with the microtubular cytoskeleton that underlies the cell body membrane, whereas the flagellar membrane isoform iso- 1 does not associate with the cytoskeleton. Deletion mutants that remove the first 25 or more amino acids from iso-1 are retargeted from the flagellum to the pellicular membrane, suggesting that these deletions remove a signal required for flagellar targeting. Unlike the full-length iso-1 protein, these deletion mutants associate with the cytoskeleton. Our results suggest that cytoskeletal binding serves as an anchor to localize the iso-2 transporter within the pellicular membrane, and that the flagellar targeting signal of iso-1 diverts this transporter into the flagellar membrane and away from the pellicular microtubules.
UR - http://www.scopus.com/inward/record.url?scp=0031407273&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031407273&partnerID=8YFLogxK
U2 - 10.1083/jcb.139.7.1775
DO - 10.1083/jcb.139.7.1775
M3 - Article
C2 - 9412471
AN - SCOPUS:0031407273
SN - 0021-9525
VL - 139
SP - 1775
EP - 1783
JO - Journal of Cell Biology
JF - Journal of Cell Biology
IS - 7
ER -