title: Regulation of angiotensin II-induced JAK2 tyrosine phosphorylation: roles of SHP-1 and SHP-2.
abstract: Angiotensin II (ANG II) exerts its effects on vascular smooth muscle cells through G protein-coupled AT1 receptors. ANG II stimulation activates the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway by inducing tyrosine phosphorylation, activation, and association of JAK2 with the receptor. Association appears to be required for JAK2 phosphorylation. In the present study, electroporation experiments with neutralizing anti-Src homology phosphatase-1 (SHP-1) and anti-SHP-2 antibodies and time course determinations of SHP-1 and SHP-2 activation and complexation with JAK2 suggest that the tyrosine phosphatases, SHP-1 and SHP-2, have opposite roles in ANG II-induced JAK2 phosphorylation. SHP-1 appears responsible for JAK2 dephosphorylation and termination of the ANG II-induced JAK/STAT cascade. SHP-2 appears to have an essential role in JAK2 phosphorylation and initiation of the ANG II-induced JAK/STAT cascade leading to cell proliferation. The motif in the AT1 receptor that is required for association with JAK2 is also required for association with SHP-2. Furthermore, SHP-2 is required for JAK2-receptor association. SHP-2 may thus play a role as an adaptor protein for JAK2 association with the receptor, thereby facilitating JAK2 phosphorylation and activation.
authors.affiliation: Vascular Biology Center, Medical College of Georgia, Augusta 30912, Georgia, USA.
authors.forename: M B
authors.initials: MB
authors.lastname: Marrero
authors.forename: V J
authors.initials: VJ
authors.lastname: Venema
authors.forename: H
authors.initials: H
authors.lastname: Ju
authors.forename: D C
authors.initials: DC
authors.lastname: Eaton
authors.forename: R C
authors.initials: RC
authors.lastname: Venema
mesh_terms: D019943:Amino Acid Substitution; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D002478:Cells, Cultured; D018274:Electroporation; D006321:Heart / Q000502:physiology*; D006352:Heart Ventricles; D047908:Intracellular Signaling Peptides and Proteins; D053614:Janus Kinase 2; D008297:Male; D009206:Myocardium / Q000166:cytology / Q000201:enzymology*; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D017354:Point Mutation; D054645:Protein Phosphatase 1; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D051381:Rats; D017207:Rats, Sprague-Dawley; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin / Q000187:drug effects / Q000502:physiology; D011994:Recombinant Proteins / Q000378:metabolism; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D018909:src Homology Domains
chemical_list: D000906:Antibodies; D047908:Intracellular Signaling Peptides and Proteins; D011518:Proto-Oncogene Proteins; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin; D011994:Recombinant Proteins; D000804:Angiotensin II; D019000:Phosphotyrosine; D011505:Protein-Tyrosine Kinases; C507927:Jak2 protein, rat; D053614:Janus Kinase 2; D054645:Protein Phosphatase 1; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C516727:Ptpn11 protein, rat; C509250:Ptpn6 protein, rat; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases