SHP-1, an SH2 domain-containing tyrosine phosphatase, has a crucial role in hematopoiesis. Here we report that SHP-1 is associated with two major tyrosine-phosphorylated proteins in hematopoietic cells treated with the tyrosine phosphatase inhibitor, pervanadate. One of the proteins corresponds to leukocyte-associated Ig-like receptor-1 (LAIR-1), a recently cloned transmembrane protein. Molecul...

Tyr phosphorylation of the multifunctional transmembrane protein band 3 has been implicated in several erythrocyte functions and disorders. We previously demonstrated that pervanadate treatment of human erythrocytes induces band-3 Tyr phosphorylation, which is catalyzed by the sequential action of tyrosine kinase Syk and tyrosine kinase(s) belonging to the Src family. In this study, we show tha...

Fms is a tyrosine kinase-containing receptor for macrophage colony-stimulating factor (M-CSF) that regulates survival, growth, and differentiation of cells along the monocyte/macrophage lineage. M-CSF stimulation of murine myeloid FDC-P1 cells expressing Fms resulted in the tyrosine phosphorylation of a number of signal transduction proteins, including an unidentified 100-kDa protein. This 100-...

Inositol and tyrosine phosphatases have been implicated in inhibitory signaling by an Fc receptor for immunoglobulin G, Fc RIIB, in B cells, mast cells, and monocytes. Here, we propose a role for the Src homology 2 (SH2)-containing tyrosine phosphatase-1 (SHP-1) in Fc RIIB-mediated inhibition of Fc R signaling. Coexpression of SHP-1 enhances Fc RIIB-mediated inhibition of Fc RIIA phagocytosis i...

Protein-tyrosine phosphatase SHP-1 is the key negative regulator of numerous signaling pathways. SHP-1 is expressed in the hematopietic and epithelial cells as two structurally similar mRNA transcripts controlled by two different promoters designated P2 and P1, respectively. Whereas the transcriptional regulation of the SHP-1 gene P1 promoter has been partially elucidated, the structure and fun...

MicroRNAs (miRNAs, miRs) are genomically encoded small approximately 22 nt RNA molecules that have been shown to mediate translational repression of target mRNAs involved in cellular proliferation, differentiation and death. Despite intensive studies on their physiological and pathological functions, the molecular mechanism of how miRNA gene transcription is regulated remains largely unknown. M...

SHP-1, an src homology 2 (SH2) domain containing protein tyrosine phosphatase, functions as a negative regulator of signaling downstream of cytokine receptors, receptor tyrosine kinases and receptor complexes of the immune system. Dephosphorylation of receptors and/or receptor-associated kinases has been described as the mechanism for the function of SHP-1. Here we demonstrate a novel mechanism...

Paired immunoglobulin-like receptor B (PIR-B) partially mediates the regeneration-inhibiting effects of the myelin-derived protein Nogo, myelin-associated glycoprotein (MAG), and oligodendrocyte-myelin glycoprotein (OMgp). In this study, we report that inhibition of the PIR-B signaling cascades in neurons enhances axon regeneration in the central nervous system (CNS). Binding of MAG to PIR-B le...

The small heterodimer partner (SHP) is an orphan nuclear receptor that lacks the DNA binding domain while conserves a putative ligand-binding site, thought that endogenous ligands for this receptor are unknown. Previous studies have determined that SHP activation protects against development of liver fibrosis a process driven by trans-differentiation and activation of hepatic stellate cells (HS...

Signal transducer and activator of transcription (STAT) proteins are both tyrosine- and serine-phosphorylated, mediating signal transduction and gene regulation. Following gene regulation, STAT activity in the nucleus is then terminated by a nuclear protein phosphatase(s), which remains unidentified. Using novel antibody arrays to screen the Stat1-specific protein phosphatase(s), we identified ...