INVESTIGADORES
PAVAROTTI Martin Alejandro
congresos y reuniones científicas
Título:
RAB COUPLING PROTEIN BINDS TO PHAGOSOMES BY
Autor/es:
PAVAROTTI M; LEIVA N.; COLOMBO MI; DAMIANI MT
Lugar:
Pinamar. Buenos Aires. Argentina
Reunión:
Congreso; XLI Reunión científica anual de la Sociedad Argentina de Bioquímica y Biología Molecular.; 2005
Institución organizadora:
ociedad Argentina de Bioquímica y Biología Molecular.
Resumen:
Rab Coupling Protein (RCP) is a member of the newly identified
class I Rab11 Family of Interacting Proteins (FIPs). RCP binds
Rab11 tightly via a Rab Binding Domain located at its C-terminus.
The N-end region of RCP has a C2 phospholipid-binding domain.
Using confocal microscopy and biochemical assays, we have
previously shown that RCP regulates phagocytosis and recycling
from the phagosomal compartment in macrophages. To further
characterize the binding of RCP to phagosomal membranes, we use
truncated forms of this protein fused to the green fluorescent protein.
The C-terminus of RCP (CT-RCP) displays a membrane-bound
pattern and alters endosomal compartment. We observed CT-RCP
associated as discrete patches to phagosomes. On the contrary, Nterminus
of RCP (NT-RCP) has a diffuse distribution resembling a
soluble protein. Neither association to early and recycling
endosomes nor to early phagosomes could be observed. Stimulation
of phosphatidic acid synthesis (a lipid to which RCP preferentially
binds) results in the translocation of NT-RCP from the cytosol to
the plasma membrane. However, we still could not observe any
association of NT-RCP to early phagosomes after PMA treatment.
Therefore, these results suggest that RCP is associated to
phagosomes via a direct interaction with Rab11 and that the C2
domain is required to target vesicles departing from the phagosomal
compartment to the plasma membrane. These events could be
important for the understanding of molecular mechanisms involved
in antigen presentation.