PTPROt: An alternatively spliced and developmentally regulated B- lymphoid phosphatase that promotes G0/G1 arrest

Ricardo C.T. Aguiar, Yoshihiro Yakushijin, Samir Kharbanda, Sanjay Tiwari, Gordon J. Freeman, Margaret A. Shipp

Research output: Contribution to journalArticlepeer-review

70 Scopus citations


Protein tyrosine phosphatases (PTP) regulate the proliferation, differentiation, and viability of lymphocytes by modulating their signaling pathways. By using the differential display assay, we have cloned a putative receptor-type PTP, which is predominantly expressed in B-lymphoid tissues (lymph nodes and spleen). This PTP, termed PTPROt (truncated), is a tissue- specific alternatively-spliced form of a human epithelial PTP, PTPRO (PTPU2/GLEPP1). Whereas the epithelial PTPRO includes an ≃800-amino acid extracellular domain, the major (3 kb) PTPROt cDNA predicts a unique 5' untranslated region and truncated (8 amino acids) extracellular domain with a conserved transmembrane region and single catalytic domain. PTPROt cDNAs encode functional ~47-kD and ~43-kD PTPs, which are most abundant in normal naive quiescent B cells and decreased or absent in germinal center B cells and germinal center-derived diffuse large B-cell lymphomas. Because PTPROt was predominantly expressed in naive quiescent B cells, the enzyme's effects on cell-cycle progression were examined. When multiple stable PTPROt sense, antisense, and vector only B-cell transfectants were grown in reduced serum and synchronized with nocodazole, PTPROt sense clones exhibited markedly increased G0/G1 arrest. Taken together, these data implicate PTPROt in the growth control of specific B-cell subpopulations.

Original languageEnglish (US)
Pages (from-to)2403-2413
Number of pages11
Issue number7
StatePublished - Oct 1 1999
Externally publishedYes

ASJC Scopus subject areas

  • Hematology
  • Biochemistry
  • Cell Biology
  • Immunology


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