Publications (65) View all
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Article: IGF-I induced rapid recruitment of integrin beta1 to lipid rafts is Caveolin-1 dependent.
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ABSTRACT: Caveolin-1 (Cav-1) regulates both insulin like growth factor receptor (IGF-IR) and integrin beta1 function. However, the role of Cav-1 in IGF-IR/integrin beta1 cross talk remains to be established. In this study, we observed that IGF-I did not induce integrin beta1 internalization but its plasma membrane reorganization. In particular, we found a rapid and transient association between integrin beta1 and Cav-1 followed by the enrichment of integrin beta1 in lipid rafts. To determine the role of Cav-1 in this process, we transfected Hacat cells with small interfering RNA specific for Cav-1 (siRNA-Cav-1) and with a scrambled siRNA as control (siRNA-Ctr). Cav-1 down regulated Hacat cells were then stimulated with IGF-I and analyzed by immunofluorescence and flow cytometry. We found that Cav-1 silencing abolished the recruitment of integrin beta1 to lipid rafts in the presence of IGF-I. These data demonstrate that IGF-IR/integrin beta1 cross talk is followed by integrin beta1 lipid raft compartmentalization and that Cav-1 is required for this process.Biochemical and Biophysical Research Communications 02/2009; 380(3):489-92. · 2.48 Impact Factor -
Article: Identification of an import signal for, and the nuclear localization of, human lactoferrin.
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ABSTRACT: Many different unique functions have been attributed to lactoferrin (Lf), including DNA and RNA binding, and transport into the nucleus, where Lf binds to specific sequences and activates transcription. A pentapeptide, Gly-Arg-Arg-Arg-Arg, corresponding to a region of the N-terminal portion of human Lf rich in basic amino acids, was synthesized and its intracellular localization was investigated. Peptide internalization was assayed using the rhodaminated form of the same molecule. This N-terminal peptide sequence is able to be internalized within less than 10 min at concentration as low as 1 microM, and its intracellular localization is nuclear, mainly nucleolar. Similar behaviour was observed using peptides composed of either all l or d amino acids, the last one being a retro-inverse peptide. The internalization process does not involve an endocytotic pathway, since no inhibition of the uptake was observed at 4 degrees C. The kinetics of peptide internalization was also evaluated. The internalization properties of such a short Lf pentapeptide have been assayed for its ability to transport peptide nucleic acids (PNAs) inside cells in order to improve their efficacy. The abundant transmembrane transport and nuclear localization of the proposed peptide, deriving from hLf and, for the first time, identified as a nuclear localization signal, could be used as an alternative strategy to tackle the unsolved problem of intracellular accumulation of antisense and antigene drugs and for the development of new pharmacological tools.Biotechnology and Applied Biochemistry 01/2002; 34(Pt 3):151-9. · 1.53 Impact Factor -
Article: Extracellular processing of amphoterin generates a peptide active on erythroleukaemia cell differentiation.
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ABSTRACT: The release of amphoterin by murine erythroleukaemia cells exposed to the chemical inducer hexamethylenebisacetamide represents an essential step for the process of their terminal differentiation. Once exported in the culture medium, amphoterin undergoes limited proteolysis, catalysed by a serine proteinase also secreted by stimulated cells. The isolated proteinase is responsible for degradation of amphoterin, with the production of a 10-amino-acid-residue fragment, specifically retaining the cell-differentiation-stimulating activity of the native protein molecule. This peptide does not express other properties of amphoterin, such as protein kinase C-stimulating activity or systemic toxicity. These findings define a selective mechanism accounting for extracellular amphoterin functional maturation.Biochemical Journal 08/2001; 357(Pt 2):569-74. · 4.90 Impact Factor -
Article: Simulated microgravity induces alteration in the central nervous system.
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ABSTRACT: To investigate whether the signs of neurophysiological impairment observed in flight may be traced back to cytomorphology, we undertook a ground-based study focusing upon the architecture of cultured glial cells under simulated microgravity obtained by three-dimensional clinorotation.Journal of gravitational physiology: a journal of the International Society for Gravitational Physiology 08/2001; 8(1):P93-5. -
Article: Immunocytochemical localization of serotonin in embryos, larvae and adults of the lancelet, Branchiostoma floridae.
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ABSTRACT: Serotonin (5-hydroxytryptamine) is a biogenic amine distributed throughout the metazoans and has an old evolutionary history. It is involved as a developmental signal in the early morphogenesis of both invertebrates and vertebrates, whereas in adults it acts mainly as a neurotransmitter and gastrointestinal hormone. In vertebrates, serotonin regulates the morphogenesis of the central nervous system and the specification of serotonergic as well as dopaminergic neurons. The present study uses, as an experimental model, an invertebrate chordate, the lancelet Branchiostomafloridae, characterized by its remarkable homologies with vertebrates that allows the 'bauplan' of the probable ancestor of vertebrates to be outlined. In particular, the involvement of serotonin as a developmental signal in embryos and larvae, as well as a neurotransmitter and gastrointestinal hormone in adult specimens of Branchiostoma floridae, gives further support to a common origin of cephalocordates and vertebrates.The Histochemical Journal 08/2001; 33(7):413-20.
