Disease relevance of Ptbp1

• In normally cultured neuroblastoma cells, these src RNA foci contain PTB, but little KSRP [1].
• The IRES of a neurovirulent picornavirus, the GDVII strain of Theiler's murine encephalomyelitis virus, requires polypyrimidine tract-binding protein (PTB) for its function [2].
• PTB deleted of its NES, unlike wild type PTB, does not stimulate the export of hepatitis B virus RNA [3].
• The specificity of binding in the UV-crosslink of sPTB to the internal ribosome entry site (IRES) of foot-and-mouth-disease virus (FMDV) is similar to that of human PTB [4].
• Polypyrimidine tract-binding protein binds to the leader RNA of mouse hepatitis virus and serves as a regulator of viral transcription [5].

High impact information on Ptbp1

• Shc proteins possess SH2 and PTB domains and serve a scaffolding function in signaling by a variety of receptor tyrosine kinases [6].
• The PTB interacting protein raver1 regulates alpha-tropomyosin alternative splicing [7].
• Heterologous recruitment of raver1, or just its C-terminus, induced very high levels of exon 3 skipping, bypassing the usual need for PTB binding sites downstream of exon 3 [7].
• Here we show that raver1 is able to promote the smooth muscle-specific alternative splicing of TM by enhancing PTB-mediated repression of exon 3 [7].
• Raver1 was identified in two-hybrid screens by its interactions with the cytoskeletal proteins actinin and vinculin, and was also found to interact with PTB [7].

Biological context of Ptbp1

• Raver1 colocalizes with polypyrimidine tract binding protein (PTB)/hnRNPI, a protein involved in RNA splicing of microfilament proteins, in the perinucleolar compartment and forms complexes with PTB/hnRNPI [8].
• Characterization of the nuclear export signal of polypyrimidine tract-binding protein [3].
• The aim of this study was to further elucidate the role of the polypyrimidine tract binding protein (PTB) in the control of insulin mRNA stability [9].
• To further test the hypothesis that PTB controls insulin gene expression, betaTC-6 cells were treated with a PTB-specific siRNA to modify the beta-cell content of PTB [9].
• The sPTB amino acid sequence is highly homologous to the human PTB sequence (97% identity), and the sPTB sequence corresponds to that of the longest human PTB, PTB4 [4].

Anatomical context of Ptbp1

• Colocalization experiments of KSRP with PTB in a mouse neuroblastoma cell line determined that both proteins are present in the perinucleolar compartment (PNC), as well as in other nuclear enrichments [1].
• In contrast, HeLa cells do not show prominent KSRP staining in the PNC, even though PTB labeling identified the PNC in these cells [1].
• In the neurons of adult mouse cerebrum and cerebellum expression of PTB is undetectable [10].
• PTB is expressed in choroid plexi and ependyma at all the stages of development and temporarily in the mantle layer of migrating neuroblasts of fore-, mid- and hindbrain and in the external granular layer of cerebellum [10].
• Raver1, a dual compartment protein, is a ligand for PTB/hnRNPI and microfilament attachment proteins [8].

Associations of Ptbp1 with chemical compounds

• We observed that the glucose- or interleukin-1beta-induced increase in insulin mRNA was paralleled by an increase in PTB mRNA [9].
• The Shc adaptor protein contains two phosphotyrosine [Tyr(P)]binding modules--an N-terminal Tyr(P) binding (PTB) domain and a C-terminal Src homology 2 (SH2) domain [11].
• Microsequencing revealed that this protein is the rat homologue of the mouse and human poly Pyrimidine Tract binding protein (PTB), which has been shown to bind to premRNA and may participate in RNA splicing [12].
• Fluoxetine (1.45 or 2.9 micromol/kg i.p.) doses that fail to change the PTB-induced loss of righting reflex and the level of brain ALLO in group-housed mice normalized both parameters in socially-isolated mice [13].
• Comparison of the patterns of cytokine induction and intracellular signaling events in DCs treated by PT and PTB revealed that although PT, like lipopolysaccharide, triggered both MyD88-dependent and -independent pathways, PTB preferentially triggered MyD88-independent pathways [14].

Regulatory relationships of Ptbp1

• It enhanced redistribution of the nuclear polypyrimidine tract-binding protein but had no influence on the localization of the nuclear splicing factor SC-35 [15].

Other interactions of Ptbp1

• Thus, in the embryonic brain expression patterns of PTB and brPTB overlap, but in the course of brain development the patterns become complementary to each other [10].

Analytical, diagnostic and therapeutic context of Ptbp1

• We have characterized expression patterns of the PTB and brPTB in course of mouse brain development, using mRNA in situ hybridization [10].
• This finding was corroborated by subsequent Western blot experiments using a PTB-specific antibody [12].
• By UV cross-linking and immunoprecipitation studies using cellular extracts and a recombinant PTB, we have established that PTB binds to the MHV plus-strand leader RNA specifically [5].
• Expression, crystallization and preliminary X-ray studies of the recombinant PTB domain of mouse dok1 protein [16].

References