Regulation of K-Cl cotransport by Syk and Src protein tyrosine kinases in deoxygenated sickle cells

Merciris, Patrick; Claussen, William J.; Joiner, Clinton H.; Giraud, Françoise

doi:10.1007/s00424-003-1025-z

Cited by 21 publications

(14 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…26,28,29 Tyrosine phosphorylation modulates the system in complex ways, with some tyrosine kinase inhibitors activating KCC 33 and others inhibiting. 34,35 Some of these effects may be mediated by modulation of protein phosphatase activity by tyrosine phosphorylation 36 and may explain the complex kinetics that have prompted more complicated models of KCC activation. 1,37 Nevertheless, a 2-stage model involving activation by protein phosphatase(s) and inactivation by a volume-sensitive kinase explains most of the kinetics of KCC activation (for more detail, see Document S1, available on the Blood website; see the Supplemental Materials link at the top of the online article).…”

Section: Discussionmentioning

confidence: 99%

Urea stimulation of KCl cotransport induces abnormal volume reduction in sickle reticulocytes

Joiner

Rettig

Jiang

et al. 2006

Blood

View full text Add to dashboard Cite

KCl cotransport (KCC) activity contributes to pathologic dehydration in sickle (SS) red blood cells (RBCs). KCC activation by urea was measured in SS and IntroductionThe KCl cotransporter (KCC) mediates electroneutral coupled transport of K ϩ and Cl Ϫ in a variety of cell types. 1,2 KCC activation results in net efflux of KCl from cells with high potassium content, with accompanying water loss and volume reduction. KCC is active in reticulocytes and diminishes with red cell maturation. 3,4 It is thought to function physiologically to reduce red blood cell (RBC) volume and establish the high cellular hemoglobin concentration (CHC) characteristic of mature cells. KCC is activated in vitro by cell swelling, acid pH, sulfhydryl oxidation/alkylation, and exposure to urea, but the relative importance of these stimuli in vivo is unknown.In RBCs containing sickle hemoglobin (Hb S), KCC activity is high, in part because of the high percentage of reticulocytes. 4 However, Hb S or Hb C in trait RBCs (AS or AC) with normal mean cell age, or after incorporation into normal RBC ghosts, appears to increase KCC activity. 5,6 Expression of Hb S or C in transgenic mice also increases red cell KCC activity. 7 Recently, we demonstrated an abnormal response to acid pH in SS RBCs that was partially corrected by incubation with the sulfhydryl reducing agent, dithiothreitol. 8 These findings suggested that regulation of KCC is abnormal in SS RBCs.As a volume regulator, KCC activity is responsive to CHC. 9,10 KCC is activated on cell swelling, and, as KCl is lost, cell volume falls, cellular hemoglobin concentration increases, and transport activity diminishes. The resultant CHC thus reflects the physiologic "volume set point" of the system. The inactivation of KCC as the cell shrinks toward its new steady state is most likely a key factor in defining the volume regulatory function of the transporter, which in turn is crucial for establishing the steady state CHC for RBCs in vivo.Volume reduction mediated by KCC has been demonstrated with RBC density measurements. 7,11,12 However, these studies, like flux studies, are complicated by varying numbers of reticulocytes (or young cells) in unfractionated SS blood, which preclude comparisons of KCC-mediated volume reduction in SS and AA cells. We recently compared the RVD mediated by KCC and stimulated by cell swelling and acid pH in SS and AA reticulocytes by tracking the changes in reticulocyte CHC by means of density gradient analysis. 8 Acid-stimulated volume reduction was exaggerated in SS reticulocytes and was diminished by sulfhydryl reduction, parallel to the behavior of KCC flux activity. However, despite the normal response of KCC flux activation to cell swelling in SS RBCs, swelling-stimulated volume reduction was markedly abnormal in SS reticulocytes and resulted in higher final CHC than in AA reticulocytes. Thus, volume reduction and KCC fluxes appear to reflect different functional aspects of the KCC system in RBCs and may be subject to different pathologic influences in SS RBCs...

show abstract

Section: Discussionmentioning

confidence: 99%

Urea stimulation of KCl cotransport induces abnormal volume reduction in sickle reticulocytes

Joiner

Rettig

Jiang

et al. 2006

Blood

View full text Add to dashboard Cite

show abstract

“…S4). Because many of these transporters are also regulated by tyrosine phosphorylation (49,50), and because their malfunction can contribute to human disease, it will be important in the future to determine whether their structures contain a functional SH2-like motif similar to that discovered here and whether their mechanism of regulation resembles that depicted in Fig. 4E.…”

Section: Discussionmentioning

confidence: 99%

“…With the evidence for a functional SH2-like motif in the membrane-spanning domain of band 3 now established, and with considerable data showing that many other membrane-spanning solute transporters are also regulated by tyrosine kinases (49,50), the question naturally arose of whether other membrane-spanning proteins might have evolved a similar functional SH2 signature sequence to enable their regulation by tyrosine kinases. Examination of the literature reveals that sequences similar to GSFLVR can indeed be found in numerous transport proteins, ranging from neurotransmitter symporters to glucose transporters to cation-Cl − electroneutral cotransporters, etc.…”

Section: Discussionmentioning

confidence: 99%

Global transformation of erythrocyte properties via engagement of an SH2-like sequence in band 3

Puchulu-Campanella

Turrini

2016

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Src homology 2 (SH2) domains are composed of weakly conserved sequences of ∼100 aa that bind phosphotyrosines in signaling proteins and thereby mediate intra-and intermolecular protein-protein interactions. In exploring the mechanism whereby tyrosine phosphorylation of the erythrocyte anion transporter, band 3, triggers membrane destabilization, vesiculation, and fragmentation, we discovered a SH2 signature motif positioned between membrane-spanning helices 4 and 5. Evidence that this exposed cytoplasmic sequence contributes to a functional SH2-like domain is provided by observations that: (i) it contains the most conserved sequence of SH2 domains, GSFLVR; (ii) it binds the tyrosine phosphorylated cytoplasmic domain of band 3 (cdb3-PO 4 ) with K d = 14 nM; (iii) binding of cdb3-PO 4 to erythrocyte membranes is inhibited both by antibodies against the SH2 signature sequence and dephosphorylation of cdb3-PO 4 ; (iv) label transfer experiments demonstrate the covalent transfer of photoactivatable biotin from isolated cdb3-PO 4 (but not cdb3) to band 3 in erythrocyte membranes; and (v) phosphorylation-induced binding of cdb3-PO 4 to the membrane-spanning domain of band 3 in intact cells causes global changes in membrane properties, including (i) displacement of a glycolytic enzyme complex from the membrane, (ii) inhibition of anion transport, and (iii) rupture of the band 3-ankyrin bridge connecting the spectrin-based cytoskeleton to the membrane. Because SH2-like motifs are not retrieved by normal homology searches for SH2 domains, but can be found in many tyrosine kinase-regulated transport proteins using modified search programs, we suggest that related cases of membrane transport proteins containing similar motifs are widespread in nature where they participate in regulation of cell properties.SH2 domain motif | tyrosine phosphorylation | erythrocyte glycolysis | anion exchanger 1 | regulation of transport proteins P rotein tyrosine phosphorylation is involved in the regulation of most cellular process, including proliferation, survival, differentiation, responses to stress, and control of cell shape/motility (1). Whereas phosphotyrosine binding (PTB) domains may mediate association with tyrosine-containing sequences regardless of their phosphorylation state, Src homology 2 (SH2) domains promote protein association only when critical tyrosine residues become phosphorylated. This strict dependence on tyrosine phosphorylation creates a molecular switch that can be sensitively controlled by upstream tyrosine kinases (1). Whereas some SH2 domains facilitate association between heterologous proteins in a signaling pathway, others mediate intrapolypeptide interactions that change protein conformation and thereby alter signaling function (2). In all cases, association between the SH2 domain and the interacting phosphotyrosine involves formation of weak interactions between a highly conserved G(S/T)FLVR sequence of the SH2 domain and the phosphate present on the phosphorylated tyrosine. To date, all 120 known SH2 domain...

show abstract

“…Activation involves dephosphorylation of a serine (threonine) residue, probably by protein phosphatase 1 (PP1) 9,10 or PP2A. 11 There is also evidence for control by tyrosine phosphorylation; in fact, certain tyrosine kinase inhibitors activate KCC, 12,13 whereas others inhibit, 14,15 suggesting multiple control points, including PP1 itself. 16,17 Activation by cell swelling appears to involve inhibition of a putative volume-sensitive serine/threonine kinase, which maintains the system in a phosphorylated, quiescent state.…”

Section: Introductionmentioning

confidence: 99%

KCl cotransport mediates abnormal sulfhydryl-dependent volume regulation in sickle reticulocytes

Joiner

Rettig²,

Jiang³

et al. 2004

Blood

View full text Add to dashboard Cite

IntroductionThe KCl cotransporter (KCC) is a member of the cation-chloride cotransporter family of proteins that mediate electroneutral net transport of salt to effect cell volume regulation, epithelial solute secretion and absorption, and control of intracellular ion concentrations. 1 In red blood cells (RBCs), KCC functions during reticulocyte maturation to establish the steady-state volume and mean corpuscular hemoglobin concentration (MCHC) of the mature RBC. 2,3 RBC KCC activity is stimulated in vitro by cell swelling (low MCHC), 4,5 acid pH, 6,7 and urea, 8 but the physiologic stimuli that effect reticulocyte volume reduction in vivo are not clear.KCC activation is controlled by phosphatase/kinase equilibria. Activation involves dephosphorylation of a serine (threonine) residue, probably by protein phosphatase 1 (PP1) 9,10 or PP2A. 11 There is also evidence for control by tyrosine phosphorylation; in fact, certain tyrosine kinase inhibitors activate KCC, 12,13 whereas others inhibit, 14,15 suggesting multiple control points, including PP1 itself. 16,17 Activation by cell swelling appears to involve inhibition of a putative volume-sensitive serine/threonine kinase, which maintains the system in a phosphorylated, quiescent state. 18 It is unknown whether control is mediated through phosphorylation of the transporter itself or other regulatory protein(s).KCC is also activated by sulfhydryl alkylation with Nethylmaleimide (NEM) 5,[19][20][21] and oxidation by diamide 22 or hydrogen peroxide. 23 CDNB (chloro-dinitrobenzine) stimulates KCC without a direct oxidant effect by enzymatic coupling to reduced glutathione (GSH). [24][25][26][27] Although the target of these agents is not known, it is clear that KCC activity and regulation are modulated by the oxidation state of RBC sulfhydryls.KCC activity in sickle (SS) RBCs is greatly elevated compared with normal (AA) RBCs, regardless of the activating stimulus. Some of this elevated activity is a consequence of the high percentage of reticulocytes in SS blood. 2,28 Nevertheless, there is evidence that the presence of sickle hemoglobin (Hb S, ␤ 6glu3val ) or hemoglobin C (Hb C, ␤ 6glu3lys ) directly affects the activity and properties of KCC in RBCs and RBC ghosts. [29][30][31]7 demonstrated acid stimulation of KCC in SS RBCs and showed that acidification of SS RBCs produced an increase in cell density. 6,7 Bookchin et al 32 showed that SS reticulocytes were susceptible to acid-induced dehydration and suggested that most of the dense cells in sickle blood arose from a subpopulation of SS reticulocytes with high sensitivity to KCC-mediated dehydration. Franco et al 33 found that SS reticulocytes that were dense in vivo were more susceptible to acid-induced dehydration via KCC than reticulocytes that were normally hydrated in vivo. These studies demonstrated the capacity of KCC to mediate SS RBC dehydration in vitro, but since direct comparisons with AA reticulocytes have not been made, the abnormal volume regulatory response of KCC in SS reticulocytes has not been f...

show abstract

Regulation of K-Cl cotransport by Syk and Src protein tyrosine kinases in deoxygenated sickle cells

Cited by 21 publications

References 43 publications

Urea stimulation of KCl cotransport induces abnormal volume reduction in sickle reticulocytes

Urea stimulation of KCl cotransport induces abnormal volume reduction in sickle reticulocytes

Global transformation of erythrocyte properties via engagement of an SH2-like sequence in band 3

KCl cotransport mediates abnormal sulfhydryl-dependent volume regulation in sickle reticulocytes

Contact Info

Product

Resources

About