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Noomuna P, Hausman JM, Sansoya R, Kalfa T, Risinger M, Low PS. Rapid degradation of protein tyrosine phosphatase 1B in sickle cells: Possible contribution to sickle cell membrane weakening. FASEB J 2022; 36:e22360. [PMID: 35593742 DOI: 10.1096/fj.202100809rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 04/22/2022] [Accepted: 05/10/2022] [Indexed: 11/11/2022]
Abstract
Although both protein tyrosine phosphatases and kinases are constitutively active in healthy human red blood cells (RBCs), the preponderance of phosphatase activities maintains the membrane proteins in a predominantly unphosphorylated state. We report here that unlike healthy RBCs, proteins in sickle cells are heavily tyrosine phosphorylated, raising the question regarding the mechanism underpinning this tyrosine phosphorylation. Upon investigating possible causes, we observe that protein tyrosine phosphatase 1B (PTP1B), the major erythrocyte tyrosine phosphatase, is largely digested to a lower molecular weight fragment in sickle cells. We further find that the resulting truncated form of PTP1B is significantly less active than its intact counterpart, probably accounting for the intense tyrosine phosphorylation of Band 3 in sickle erythrocytes. Because this tyrosine phosphorylation of Band 3 promotes erythrocyte membrane weakening that causes release of both membrane vesicles and cell free hemoglobin that in turn initiates vaso-occlusive events, we conclude that cleavage of PTP1B could contribute to the symptoms of sickle cell disease. We further posit that methods to inhibit proteolysis of PTP1B could mitigate symptoms of the disease.
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Affiliation(s)
- Panae Noomuna
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA.,Institute for Drug Discovery, Purdue University, West Lafayette, Indiana, USA
| | - John M Hausman
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA.,Institute for Drug Discovery, Purdue University, West Lafayette, Indiana, USA
| | - Ruhani Sansoya
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
| | - Theodosia Kalfa
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Mary Risinger
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Philip S Low
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA.,Institute for Drug Discovery, Purdue University, West Lafayette, Indiana, USA
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