A maize insulin-like growth factor signals to a transduction pathway that regulates protein synthesis in maize
Por:
García Flores C., Aguilar R., Reyes De La Cruz H., Albores M., Sánchez de Jiménez E.
Publicada:
1 ene 2001
Resumen:
Insulin and insulin-like growth factors (IGFs) are well-characterized regulators in higher eukaryotic cells that control biological processes such as cell growth and survival, and selective translation of mRNAs. This research presents the purification of a 20 kDa protein, isolated from maize tissue, with IGF activity. The protein was purified from 48 h-germinated maize embryonic axes by G-50 Sephadex fractionation followed by affinity chromatography through a bovine insulin antibody-Sepharose column. This protein proved to significantly speed up maize germination and seedling growth. At the molecular level, Zea mays IGF (ZmIGF) enhanced phosphorylation of S6 ribosomal protein (rp) on the 40 S ribosomal subunit, in a similar way as observed when bovine insulin is applied to maize axes during germination. Rapamycin, a specific inhibitor of the insulin-stimulated signal transduction pathway, prevented S6 rp phosphorylation in maize axes. Moreover, ZmIGF stimulated [35S]methionine incorporation into rps, above the level of overall cytoplasmic proteins. Either incubation with anti-insulin antibody, heat treatment (60 °C) or trypsin digestion abolished this ZmIGF effect. It is proposed that ZmIGF is an endogenous maize growth factor that regulates the synthesis of specific proteins through a pathway similar to that of insulin or IGFs in animal tissues.
Filiaciones:
García Flores C.:
Departamentos de Bioquímica, Univ. Nacional Autonoma de Mexico, Circuito Institutos, Ciudad Universitaria 04510, México D.F., Mexico
Aguilar R.:
Departamentos de Bioquímica, Univ. Nacional Autonoma de Mexico, Circuito Institutos, Ciudad Universitaria 04510, México D.F., Mexico
Reyes De La Cruz H.:
Departamentos de Bioquímica, Univ. Nacional Autonoma de Mexico, Circuito Institutos, Ciudad Universitaria 04510, México D.F., Mexico
Albores M.:
Departamentos de Bioquímica, Univ. Nacional Autonoma de Mexico, Circuito Institutos, Ciudad Universitaria 04510, México D.F., Mexico
Sánchez de Jiménez E.:
Departamentos de Bioquímica, Univ. Nacional Autonoma de Mexico, Circuito Institutos, Ciudad Universitaria 04510, México D.F., Mexico
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