Characterization of glyceraldehyde-3-phosphate dehydrogenase as a novel transferrin receptor.

Kumar, Santosh and Sheokand, Navdeep and Mhadeshwar, Mayur Anant and Raje, Chaaya Iyengar and Raje, Manoj (2012) Characterization of glyceraldehyde-3-phosphate dehydrogenase as a novel transferrin receptor. The international journal of biochemistry & cell biology, 44 (1). pp. 189-99. ISSN 1878-5875

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Abstract

A majority of cells obtain of transferrin (Tf) bound iron via transferrin receptor 1 (TfR1) or by transferrin receptor 2 (TfR2) in hepatocytes. Our study establishes that cells are capable of acquiring transferrin iron by an alternate pathway via GAPDH. These findings demonstrate that upon iron depletion, GAPDH functions as a preferred receptor for transferrin rather than TfR1 in some but not all cell types. We utilized CHO-TRVb cells that do not express TfR1 or TfR2 as a model system. A knockdown of GAPDH in these cells resulted in a decrease of not only transferrin binding but also associated iron uptake. The current study also demonstrates that, unlike TfR1 and TfR2 which are localized to a specific membrane fraction, GAPDH is located in both the detergent soluble and lipid raft fractions of the cell membrane. Further, transferrin uptake by GAPDH occurs by more than one mechanism namely clathrin mediated endocytosis, lipid raft endocytosis and macropinocytosis. By determining the kinetics of this pathway it appears that GAPDH-Tf uptake is a low affinity, high capacity, recycling pathway wherein transferrin is catabolised. Our findings provide an explanation for the detailed role of GAPDH mediated transferrin uptake as an alternate route by which cells acquire iron.

Item Type:	Article
Additional Information:	Copyright of this article belongs to Elsevier Science.
Uncontrolled Keywords:	Transferrin receptor; Glyceraldehyde-3-phosphate dehydrogenase; Iron; Transferrin; Multifunctional protein
Subjects:	Q Science > QR Microbiology
Depositing User:	Dr. K.P.S.Sengar
Date Deposited:	27 Jan 2012 15:32
Last Modified:	27 Jan 2012 15:32
URI:	http://crdd.osdd.net/open/id/eprint/689

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