Expression and intracellular localization of Pyk2 in normal and v-src transformed chicken epiphyseal chondrocytes.
The expression and localization of prolin-rich tyrosine kinase 2 (Pyk2) were studied in chick embryo epiphyseal chondrocytes. Two immunoreactive bands were detected in chondrocytes, a major band with an apparent Mr of 123 kDa and a minor band with an apparent Mr of 68 kDa. The major band appears to migrate as a doublet with apparent Mr of 116/123 kDa. Increased levels of the three forms of Pyk2 were observed in v-src transformed chondrocytes as compared to control uninfected chondrocytes. Immunofluorescent staining shows that Pyk2 is clearly visible in the cytosol and in the perinuclear region of control and v-src-chondrocytes and displays a pattern very similar to the distribution of the mitochondrial marker Mito Tracker. More, immunofluorescent staining shows that Pyk2 is nuclear in most chondrocytes. By subcellular fractionation, the p116/123 Pyk2 doublet, was found to be accumulated mainly in the cytoplasm while the p68 Pyk2 form, was found to be accumulated exclusively in the nucleus. The differential nuclear/cytoplasmic distribution of the Pyk2 forms remains unchanged after v-Src-induced transformation. The p68 Pyk2 form could no longer be detected by using a N-terminus domain-specific anti-Pyk2 antibody. Consistently, Pyk2 immunoreactivity was restricted to the cytoplasm of control and v-src transformed chondrocytes. Thus it appears that the p68 Pyk2 form that accumulates in the nucleus has a deletion in the N-terminus region.
Arcucci
Alessandro
A
Dipartimento di Scienze Biomorfologiche e Funzionali, Università di Napoli Federico II, via S. Pansini n. 5, 80131 Napoli, Italy.
Montagnani
Stefania
S
Gionti
Elisa
E
D000818:Animals; D002467:Cell Nucleus / Q000201:enzymology; D002478:Cells, Cultured; D002642:Chick Embryo; D019902:Chondrocytes / Q000378:metabolism / Q000648:ultrastructure*; D003593:Cytoplasm / Q000201:enzymology; D004838:Epiphyses; D051418:Focal Adhesion Kinase 2 / Q000096:biosynthesis*; D008928:Mitochondria / Q000201:enzymology; D015688:Oncogene Protein pp60(v-src) / Q000235:genetics*; D014170:Transformation, Genetic
D051418:Focal Adhesion Kinase 2; D015688:Oncogene Protein pp60(v-src)