Brefeldin A (BFA) Inhibits Basolateral Membrane (BLM) Delivery and Dimerization of Transcobalamin II Receptor in Human Intestinal Epithelial Caco-2 Cells

Bose, Santanu; Chapin, Steven J.; Seetharam, Shakuntla; Feix, Jimmy B.; Mostov, Keith E.; Seetharam, Bellur

doi:10.1074/jbc.273.26.16163

Cited by 14 publications

(2 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast, both tunicamycin and BFA seem to delay BLM delivery of TC‐R suggesting that both intact Golgi and post‐Trans‐Golgi Network (TGN) fusion events are important for its trafficking to BLM. While tunicamycin treatment may affect trafficking of TC‐R from endoplasmic reticulum to Golgi, resulting in degradation (Elbein, 1987), we have shown previously (Bose et al 1998) that BFA treatment results in accumulation of TC‐R in a non‐sialylated form. Treatment with wortmannin is known to delay trafficking of some cell surface receptors such as cation‐indepenedent mannose 6‐phosphate (Kundra & Kornfeld, 1998) and platelet‐derived growth factor receptor (Joly et al 1995).…”

Section: Discussionmentioning

confidence: 95%

Plasma membrane delivery, endocytosis and turnover of transcobalamin receptor in polarized human intestinal epithelial cells

Bose¹,

Kalra²,

Yammani³

et al. 2007

The Journal of Physiology

Self Cite

View full text Add to dashboard Cite

Cells that are metabolically active and in a high degree of differentiation and proliferation require cobalamin (Cbl: vitamin B 12 ) and they obtain it from the circulation bound to transcobalamin (TC) via the transcobalamin receptor (TC-R). This study has investigated the plasma membrane dynamics of TC-R expression in polarized human intestinal epithelial Caco-2 cells using techniques of pulse-chase labelling, domain-specific biotinylation and cell fractionation. Endogenously synthesized TC-R turned over with a half-life (T 1/2 ) of 8 h following its delivery to the basolateral plasma membrane (BLM). The T 1/2 of BLM delivery was 15 min and TC-R delivered to the BLM was endocytosed and subsequently degraded by leupeptin-sensitive proteases. However, about 15% of TC-R endocytosed from the BLM was transcytosed (T 1/2 , 45 min) to the apical membranes (BBM) where it underwent endocytosis and was degraded. TC-R delivery to both BLM and BBM was inhibited by Brefeldin A and tunicamycin, but not by wortmannin or leupeptin. Colchicine inhibited TC-R delivery to BBM, but not BLM. At steady state, apical TC-R was associated with megalin and both these proteins were enriched in an intracellular compartment which also contained Rab5 and transferrin receptor. These results indicate that following rapid delivery to both plasma membrane domains of Caco-2 cells, TC-R undergoes constitutive endocytosis and degradation by leupeptin-sensitive proteases. TC-R expressed in apical BBM complexes with megalin during its transcytosis from the BLM.

show abstract

Section: Discussionmentioning

confidence: 95%

Plasma membrane delivery, endocytosis and turnover of transcobalamin receptor in polarized human intestinal epithelial cells

Bose¹,

Kalra²,

Yammani³

et al. 2007

The Journal of Physiology

Self Cite

View full text Add to dashboard Cite

show abstract

“…Resident proteins of the cis-, medialand trans-Golgi cisternae return to the endoplasmic retuculum upon BFA treatment [41,42], whereas the destination of proteins of the TGN is not known. Several studies indicate that these proteins of the TGN are insensitive to BFA treatment [43][44][45], whereas others support the hypothesis that the TGN proteins are BFA-sensitive [46][47][48]. Nocodazole treatment, by depolymerizing microtubules, results in the rapid redistribution of trans-Golgi and TGN proteins [49,50].…”

Section: Discussionmentioning

confidence: 99%

Biochemical characterization and subcellular localization of human copper transporter 1 (hCTR1)

Klomp

Tops

vandenBERG

et al. 2002

Biochemical Journal

165

View full text Add to dashboard Cite

The human copper transporter 1 gene (hCTR1) was previously identified by functional complementation in ctr1-deficient yeast. Overexpression of hCTR1 in wild-type yeast leads to increased sensitivity to copper toxicity, and mice with a homozygous disruption at the Ctr1 locus die early during embryogenesis. It is proposed that hCTR1 is responsible for high-affinity copper uptake into human cells, but the underlying molecular mechanisms are unknown. To begin to investigate the biochemical characteristics of hCTR1, a polyclonal antiserum was raised against recombinant hCTR1-fusion peptides. Biosynthetic studies using this antiserum revealed that hCTR1 was synthesized as a precursor protein of 28 kDa containing N-linked oligosaccharides, and is then converted to a mature protein of approx. 35 kDa, which is ubiquitously expressed. Immunofluorescence studies showed that subcellular hCTR1 localization differed markedly between cell types. In some cell lines, hCTR1 was located predominantly in an intracellular vesicular perinuclear compartment, and in others hCTR1 was located predominantly at the plasma membrane. In contrast with the copper export P-type ATPases mutated in Wilson disease and Menkes disease, the localization of hCTR1 was not influenced by copper concentrations. Inhibition of endocytosis by methyl-beta-cyclodextrin caused a partial redistribution of hCTR1 to the cell surface of HeLa cells. Taken together, the results in this study suggest a cell-specific control of copper uptake, which involves subcellular localization of the hCTR1 protein.

show abstract

Involvement of Protein Tyrosine Kinase in Osmoregulation of Na + Transport and Membrane Capacitance in Renal A6 Cells

Niisato

Driessche

Liu

et al. 2000

Journal of Membrane Biology

View full text Add to dashboard Cite

Renal A6 cells have been reported in which hyposmolality stimulates Na(+) transport by increasing the number of conducting amiloride-sensitive 4-pS Na(+) channels at the apical membrane. To study a possible role of protein tyrosine kinase (PTK) in the hyposmolality-induced signaling, we investigated effects of PTK inhibitors on the hyposmolality-induced Na(+) transport in A6 cells. Tyrphostin A23 (a PTK inhibitor) blocked the stimulatory action of hyposmolality on a number of the conducting Na(+) channels. Tyrphostin A23 also abolished macroscopic Na(+) currents (amiloride-sensitive short-circuit current, I(Na)) by decreasing the elevating rate of the hyposmolality-increased I(Na). Genistein (another type of PTK inhibitor) also showed an effect similar to tyrphostin A23. Brefeldin A (BFA), which is an inhibitor of intracellular translocation of protein, blocked the action of hyposmolality on I(Na) by diminishing the elevating rate of the hyposmolality-increased I(Na), mimicking the inhibitory action of PTK inhibitor. Further, hyposmolality increased the activity of PTK. These observations suggest that hyposmolality would stimulate Na(+) transport by translocating the Na(+) channel protein (or regulatory protein) to the apical membrane via a PTK-dependent pathway. Further, hyposmolality also caused an increase in the plasma (apical) membrane capacitance, which was remarkably blocked by treatment with tyrphostin A23 or BFA. These observations also suggest that a PTK-dependent pathway would be involved in the hyposmolality-stimulated membrane fusion in A6 cells.

show abstract

Brefeldin A (BFA) Inhibits Basolateral Membrane (BLM) Delivery and Dimerization of Transcobalamin II Receptor in Human Intestinal Epithelial Caco-2 Cells

Cited by 14 publications

References 40 publications

Plasma membrane delivery, endocytosis and turnover of transcobalamin receptor in polarized human intestinal epithelial cells

Plasma membrane delivery, endocytosis and turnover of transcobalamin receptor in polarized human intestinal epithelial cells

Biochemical characterization and subcellular localization of human copper transporter 1 (hCTR1)

Involvement of Protein Tyrosine Kinase in Osmoregulation of Na + Transport and Membrane Capacitance in Renal A6 Cells

Contact Info

Product

Resources

About