Margarida R. Barroso

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We have used temperature and nocodazole blocks in an in vivo basolateral to apical transcytosis assay to dissociate the early transcytotic steps occurring during the formation of transcytotic vesicles and their microtubule-dependent translocation into the apical region, from the late steps when transcytotic cargo is delivered into the apical media. We found(More)
Transcytosis-associated protein (TAP) is found on transytotic vesicles (TCVs) and is required for their fusion with the target membrane. We developed a cell-free assay capable of differentiating targeting/binding of TCVs to membrane from later fusion events. We found that TAP mediates stable association of TCVs with the target membrane. The sequence of rat(More)
We previously demonstrated that mRNAs for the subunits of the Arp2/3 complex localize to protrusions in fibroblasts (Mingle et al. in J Cell Sci 118:2425–2433, 2005). However, the signaling pathway that regulates Arp2/3 complex mRNA localization remains unknown. In this study we have identified lysophosphatidic acid (LPA) as a potent inducer of Arp2 mRNA(More)
The MDR-1 gene product, plasma membrane glycoprotein or P-glycoprotein (PGP), has been shown to confer drug resistance to cancer cells by acting as an energy-dependent drug-efflux pump. We have examined the endocytic traffic of PGP in human multidrug-resistant cells and tested whether the traffic and the steady-state intracellular localization of PGP can be(More)
Previously, FRET confocal microscopy has shown that polymeric IgA-receptor (pIgA-R) is distributed in a clustered manner in apical endosomes. To test whether different membrane-bound components form clusters during membrane trafficking, live-cell quantitative FRET was used to characterize the organization of pIgA-R and transferrin receptor (TFR) in(More)
Previously, we have shown that p22, an EF-hand Ca2+-binding protein, interacts indirectly with microtubules in an N-myristoylation-dependent and Ca2+-independent manner. In the present study, we report that N-myristoylated p22 interacts with several microtubule-associated proteins within the 30-100 kDa range using overlay blots of microtubule pellets(More)
Proteins containing the EF-hand Ca(2+)-binding motif, such as calmodulin and calcineurin B, function as regulators of various cellular processes. Here we focus on p22, an N-myristoylated, widely expressed EF-hand Ca(2+)-binding protein conserved throughout evolution, which was shown previously to be required for membrane traffic. Immunofluorescence studies(More)
Antigen processing and MHC class II-restricted antigen presentation by antigen-presenting cells such as dendritic cells and B cells allows the activation of naïve CD4+ T cells and cognate interactions between B cells and effector CD4+ T cells, respectively. B cells are unique among class II-restricted antigen-presenting cells in that they have a clonally(More)
Quantum dots (QDs) promise to revolutionize the way fluorescence imaging is used in the cell biology field. The unique fluorescent spectral characteristics, high photostability, low photobleaching, and tight emission spectra of QDs position them above traditional dyes. We will address the ability of water-stabilized QDs to behave as effective fluorescence(More)
Single clonal tracing and analysis at the whole-heart level can determine cardiac progenitor cell behavior and differentiation during cardiac development, and allow for the study of the cellular and molecular basis of normal and abnormal cardiac morphogenesis. Recent emerging technologies of retrospective single clonal analyses make the study of cardiac(More)