Modulation of erythrocyte deformability by PKC activity

Abstract

The interactions between membrane, peripheral and cytoskeleton proteins are responsible for the maintenance of erythrocyte deformability (EEI) and some of these interactions are modulated by PKC activity. Protein band 3 of the erythrocyte membrane is phosphorylated by phosphotyrosine kinases (PTK) and dephosphorylated by phosphotyrosine phosphatase (PTP).It was previously described by us a signal transduction mechanism that describes a possible pathway connecting an erythrocyte external membrane protein, acetylcholinesterase (AChE), with protein band 3.So how does PKC activity modulate EEI when protein band 3 is phosphorylated or dephosphorylated in absence or presence of AChE effectors?To answer this we used phorbol 12-myristate 13-acetate (PMA) as an activator and chelerythrine chloride as inhibitor of PKC and also band 3 modulators of band 3 phosphorylation degree, in presence and absence of AChE effectors in order to measure in whole blood samples EEI.Our results showed that erythrocyte deformability was significantly (i) decreased by inhibition of PKC, in absence and presence of AChE inhibitor velnacrine (ii) increased with PMA in absence and presence of ACh and (iii) decreased in presence of calpeptin in absence and presence of either chelerythrine or PMA.These results establish dependence between cytoskeleton proteins, PKC activity, band 3 phosphorylation degrees and EEI. Better understanding of those proteins interactions on transduction mechanisms might trigger possible targets for drug action that would modulate EEI.

Targeted quantitative phosphoproteomic analysis of erythrocyte membranes during blood bank storage

“…[14][15][16] The major functional consequence of these phosphorylation events is a decreased membrane mechanical stability due to alterations of cytoskeletonmembrane interactions. [15][16][17][18] However, knowledge of the influence of membrane protein phosphorylation on erythrocyte integrity and deformability is still limited, especially in the case of stored RBCs. On the contrary, a few studies have showed changes in the phosphorylation status of membrane proteins in sickle red cells, [19][20][21][22][23] supporting the idea that some of the abnormalities, in particular those related to cell shape, of such diseased erythrocytes are associated with phosphorylation-dependent cytoskeleton disorders.…”

Amyloid beta peptide (1–42)‐mediated antioxidant imbalance is associated with activation of protein kinase C in red blood cells

“…It has been reported that upon activation, PKC induces posttranslational modifications to cytoskeleton proteins, including phosphorylation and dephosphorylation. 30 In particular, PKC isoenzymes, which phosphorylate protein serinethreonine residues, are known to phosphorylate both PTK and PTP. 31 PKC has been shown to phosphorylate and activate the kinase p72syk.…”

Role of Different Molecular Pathways in the Development of Diabetes-Induced Nephropathy

“…Also mechanical stretch mimicking the shear stress caused by hyperfiltration and increased glomerular pressure increased the excretion of VEGF in the mesangial cells. In a study demonstrating this effect it seemed that the effects of shear stress in mesangial cells are mediated via a pathway dependent on PKC and Protein Tyrosine Kinase (PTK) since the combined inhibition of these enzymes completely prevented the increased VEGF excretion in an in vitro experiment [61]. However, MC can also produce VEGF [62] and express VEGF receptors both in vitro and in pathological conditions [63].…”