Derrick Domingo

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We have evaluated transcytotic routes in MDCK cells for their ability to generate a polarized surface distribution of trafficking proteins by following the intracellular sorting of transferrin receptors (TRs). We find that the selective basolateral expression of TRs is maintained in the face of extensive trafficking between the apical and basolateral(More)
The mechanisms underlying neoplastic epithelial cell killing by ionizing radiation are largely unknown. We discovered a novel response to radiation manifested by autophagy and the development of acidic vesicular organelles (AVO). Acidification of AVO was mediated by the vacuolar H+-ATPase. Staining with the lysosomotropic agent acridine orange enabled us to(More)
Human transferrin receptors (TR) and receptors for polymeric immunoglobulins (pIgR) expressed in polarized MDCK cells maintain steady-state, asymmetric distributions on the separate basolateral and apical surfaces even though they are trafficking continuously into and across these cells. The intracellular mechanisms required to maintain these asymmetric(More)
The transcytotic pathway followed by the polymeric IgA receptor (pIgR) carrying its bound ligand (dIgA) from the basolateral to the apical surface of polarized MDCK cells has been mapped using morphological tracers. At 20 degreesC dIgA-pIgR internalize to interconnected groups of vacuoles and tubules that comprise the endosomal compartment and in which they(More)
By functional analysis of mutant human transferrin receptors (TR) expressed in chicken embryo fibroblasts, we previously identified a tetrapeptide sequence, Y20TRF23, within the 61-residue cytoplasmic tail as the signal for high-efficiency endocytosis (Collawn, J. F., Stangel, M., Kuhn, L. A., Esekogwu, V., Jing, S., Trowbridge, I.S., and Tainer, J.A.(More)
Transferrin receptors are expressed in large quantities on tissues with high requirements for iron such as maturing erythroid cells and placenta. In addition, they are found in abundance on proliferating cells from other normal tissues as well as on a variety of tumours. Recent genetic analysis has shown that structural genes for the transferrin receptor,(More)
A monoclonal antibody with specificity for murine transferrin receptor was conjugated with the toxic A subunit of ricin. The dose range, specificity, and kinetics of inhibition of protein synthesis of the conjugate were determined on the murine T-lymphoma cell line, BW5147. When toxin was present throughout the period of culture, in vitro myeloid (CFUc) and(More)