INVESTIGADORES
FERNANDEZ Maria Del Carmen
congresos y reuniones científicas
Título:
Raft-Phosphatidylinositol-4,5-Bisphosphate (Pip2) Is Essential For Tubular Organization Of Renal Papilla.
Autor/es:
MÁRQUEZ G, LEOCATA NIETO F, FERNÁNDEZ-TOME M, STERIN-SPEZIALE N.; M. C. FERNANDEZ
Lugar:
Ajaccio, Corsica, France
Reunión:
Congreso; 46th International Conference on the Biochemistry of Lipids (ICBL).; 2005
Institución organizadora:
ICBL
Resumen:
Raft-phosphatidylinositol-4,5-bisphosphate (PI-
4,5-P2) is essential for the maintenance of mature
focal adhesion (FA) plaques
M.G.M´arquez, F. Leocata Nieto, M.L. Gagliano, M.C.
Fern´andez-Tome, N. Favale, N.B. Sterin-Speziale
School of Pharmacy and Biochemistry, University
of Buenos Aires, IQUIFIB-CONICET, Buenos Aires,
, University
of Buenos Aires, IQUIFIB-CONICET, Buenos Aires,,
Argentina
Renal papilla is a highly organized tissue whose functionality
depends on tubular organization by cell attachment
to the extracellular matrix. Mature focal adhesion
plaques (FA) are the most stable cell-matrix points
of adhesion which involves the FA-protein vinculin
(V). PI-4,5-P2, a minor membrane phospholipid usually
implicated in cell signaling, is now recognized to
be a principal molecule in tissue organization since is
required for activation of vinculin. Since, it has been
found that raft-microdomains are enriched in PI-4,5-P2
it has been recently suggested that FA have a lipidraft-
like composition, however, no direct evidence is
available respect to FA localization in specific raft
microdomains in any cellular type.
In the present work we describe, in rat renal papilla,
a specific FA-raft microdomain enriched in the typical
raft lipids: sphingomyelin and cholesterol. Such
microdomains are also largely enriched in PI-4P and
PI-4,5-P2 (32- and 5-fold increase) and in unsaturated
phosphatidylethanolamine. Immunofluorescence
analysis of cultured collecting duct cells treated with
cyclodextrine evoked disappearance of FA but V and
PI-4,5-P2 still remained in the plasma membrane
denoting that FA assembly needs raft integrity. LiCl
or neomycin treatment decreased the amount of raft
associated-V and induced FA dissipation, reflecting
that such proteins have to be bound to PI-4,5-P2 to
be assembled in a FA structure.
These results demonstrate that the existence of PI-4,5-
P2 enriched-raft is a requirement for the maintenance of
mature FAplaques that ensures the tubular organization
of adult renal tissue.