Cellular location of proteins related to iron absorption and transport

Abstract

We describe an unusual case of hepatosplenic T-cell lymphoma in a 61-year-old man who presented with fever, hepatosplenomegaly, anemia, and thrombocytopenia. A spleen biopsy was consistent with T-cell lymphoma. Cytogenetic studies did not reveal chromosome abnormalities. Using the polymerase chain reaction approach, clonality of the T-cell receptor c-chain gene rearrangement could be demonstrated, while Southern blot analysis disclosed only a germline configuration of the T-cell receptor b chain genes. Of interest, an immune-mediated mechanism was demonstrated and was most likely responsible for erythrocyte and platelet destruction; this is, therefore, the first report of cd T-cell lymphoma in association with EvansÕ syndrome. Initial steroid treatment was ef-ficacious in limiting autoimmunity but constitutional symptoms did not subside. Chem-otherapy (MACOP-B) was successful in obtaining complete clinical remission. Finally, thrombocytopenia in cd T-cell lymphoma patients should be routinely evaluated for platelet autoantibodies. Am.

Alpha-Synuclein Is a Cellular Ferrireductase

“…This ties in well with recent evidence showing the protein associated with cell membranes [3]. Most cellular ferrireductases are found integral or closely associated to the bio-membrane [28]. Also, ferrireductases commonly utilise redox cycling of copper atoms to remove electrons from iron and thus reduce Fe(III) to Fe(II).…”

Heavy Metal Poisoning and Cardiovascular Disease

“…However, other important issues are not yet fully understood, like the form of cadmium which is taken up by cells (i.e., free ion or protein bound), their expected amounts in circulation, and the precise uptake route of cadmium by the cells. Albeit, several ion channels and transporters have been described to transport cadmium across the plasma membrane, for example, calcium-channels [178], plasma membrane-associated DMT-1 [179]; it is unclear whether these mechanisms are also active in endothelial cells. …”

sAPP modulates iron efflux from brain microvascular endothelial cells by stabilizing the ferrous iron exporter ferroportin

“…Cp is expressed in both a soluble, secreted form (sCp) and a GPI-linked and therefore membrane-bound form [16][17][18]; the orientation of GPI-Cp places the ferroxidase domain in the exo-cytoplasmic space. Hp is expressed exclusively as a type I membrane protein, tethered to the plasma membrane with an exo-cytoplasmic orientation of the ferroxidase domain [13][14][15]. Both proteins are known to support iron efflux from cells via the ferrous iron exporter, ferroportin (Fpn) [19][20][21][22][23].…”