Human melanoma TrkC: its association with a purine-analog-sensitive kinase activity.
The various members of the Trk tyrosine kinase family and p75 neurotrophin receptor (p75(NTR)) have been identified as signaling receptors for the structurally related members of the neurotrophins (NT) family. We have previously reported that NT treatment of murine and human brain-metastatic melanoma cells affects their invasive capacities and increases the production of extracellular-matrix degradative enzymes. These cells express aberrant levels of functional p75(NTR) and TrkC, the putative high-affinity receptor for the neurotrophin NT-3. Here we demonstrate that, by using sensitive immune-complex kinase assays in human brain-metastatic (70W) melanoma cells, TrkC receptors associate with a kinase activity exhibiting a dose-dependent susceptibility to inhibition by the purine-analogs 6-thioguanine and 2-aminopurine. The activity of this purine-analog-sensitive kinase (PASK) was induced by NT-3 in a time-dependent fashion, phosphorylating exogenous myelin basic protein (MBP) but not denatured enolase. It is similar to the one reported to relate with p75(NTR) and TrkA receptors and stimulated by the prototypic NT, nerve growth factor. Thus, PASKs may represent unique signaling components common to NT receptors that could engage joint downstream signaling effectors in brain-metastatic melanoma.
Marchetti
Dario
D
Department of Comparative Biomedical Sciences, SVM, Louisiana State University at Baton Rouge, Baton Rouge, Louisiana 70803, USA. dmarchetti@vetmed.lsu.edu
Murry
Brian
B
Galjour
Jennifer
J
Wilke-Greiter
Andrea
A
D015075:2-Aminopurine / Q000494:pharmacology; D001932:Brain Neoplasms / Q000378:metabolism*; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008545:Melanoma / Q000378:metabolism*; D009362:Neoplasm Metastasis; D020933:Neurotrophin 3 / Q000494:pharmacology; D011494:Protein Kinases / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D020800:Receptor, Nerve Growth Factor; D020812:Receptor, trkC / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D017475:Receptors, Nerve Growth Factor / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction; D013866:Thioguanine / Q000494:pharmacology; D013997:Time Factors
D020933:Neurotrophin 3; D020800:Receptor, Nerve Growth Factor; D017475:Receptors, Nerve Growth Factor; D015075:2-Aminopurine; D011494:Protein Kinases; C478705:purine-analog-sensitive kinase, human; C116037:PAS domain kinases; D020812:Receptor, trkC; D017346:Protein Serine-Threonine Kinases; D013866:Thioguanine