INVESTIGADORES
ADAMO Hugo Pedro
congresos y reuniones científicas
Título:
Heterogeneous distribution of the human plasma membrane Ca2+ transporter expressed in yeasts
Autor/es:
CORRADI GERARDO RAUL; LEVI, VALERIA; ADAMO HUGO PEDRO
Lugar:
Buzios
Reunión:
Congreso; VII Iberoamerican Congress of Biophysics; 2009
Institución organizadora:
Brazilian Bophysical Society, SOBLA, SAB, Latin American Federation of Biophysical Societies, Portuguese Biophysical Society, Spanish Biophysical Society.
Resumen:
The Ca2+ pumps that deplete the cytosol of Ca2+
ions are crucial to Ca2+ homeostasis. The Ca2+ pump
from the plasma membrane (PMCA) is an essential component of animal cells. We
have recently shown that functional PMCA (human isoform 4xb) can be
constitutively produced in the yeast S.
cerevisiae (Cura et. al., 2008). Here we used fluorescence confocal
microscopy to investigate the localization of a PMCA-GFP fusion in the yeast
cell. Most of the expressed protein was
observed associated with perinuclear endoplasmic reticulum membranes and at the
cell periphery in the plasma membrane or just underneath it. The distribution
of fluorescence intensity at the cell cortex exhibited a marked patchy pattern
indicating that the PMCA-GFP was concentrated in discrete clusters while
excluded from other membrane domains. After
photobleaching of a limited region of the cell cortex, the initial fluorescence
recovered rapidly (<5 min) regenerating the PMCA clusters at exactly the
same location. To study the dynamics of cortical PMCA-GFP, we used fluorescence
correlation spectroscopy (FCS). These experiments showed that the protein
follows anomalous diffusion in this membrane probably due to interactions with
other components of the membrane. The fully active PMCAct120-GFP mutant ct120
lacking the C-terminal 120 residues showed a distribution pattern similar to
the PMCA-GFP. Thus, it seems that the PMCA clustering is neither mediated by
interactions via the C-terminal PDZ binding domain nor by self-association
through the C-terminal regulatory region.
With Grants from Universidad de Buenos Aires (UBACYT 009, CONICET PIP 112-200801-02022 and ANPCyT Prestamo BID
PICT 15-15-25965)