Characterization of the receptor for insulin-like growth factor on Leishmania promastigotes.
Insulin-like growth factor (IGF)-I constitutively present in the skin is one of the first growth factors that Leishmania parasites encounter after transmission to the vertebrate host. We have previously shown that IGF-I is a potent growth-promoting factor for Leishmania parasites. IGF-I binds specifically to a single-site putative receptor at the parasite membrane, triggering a cascade of phosphorylation reactions. In the present article we characterize the receptor for IGF-I on Leishmania (Leishmania) mexicana promastigotes. The receptor is a monomeric glycoprotein with a molecular mass of 65 kDa and is antigenically related to the alpha chain of human type 1 IGF-I receptor. Upon IGF-I stimulation the receptor undergoes autophosphorylation on tyrosine residues with activation of its signaling pathway. Activation of the IGF-I receptor also leads to phosphorylation of an 185-kDa molecule that is homologous to the substrate of the insulin receptor present in human cells, the insulin receptor substrate 1 (IRS-1).
Gomes
C M
CM
Laboratory of Pathology of Infectious Diseases, Department of Pathology, University of Sao Paulo, Brazil. gomescla@usp.br
Goto
H
H
Magnanelli
A C
AC
Monteiro
H P
HP
Soares
R P
RP
Corbett
C E
CE
Gidlund
M
M
D000818:Animals; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D007894:Leishmania mexicana / Q000378:metabolism*; D008970:Molecular Weight; D010766:Phosphorylation; D011233:Precipitin Tests; D017451:Receptors, Somatomedin / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism
D017451:Receptors, Somatomedin