Internalization of the interleukin 6 signal transducer gp130 does not require activation of the Jak/STAT pathway.

摘要: Signalling receptors often undergo receptor-mediated endocytosis. In many cases this internalization is stimulated by ligand binding and activation of intrinsic receptor tyrosine kinases, resulting in a down-regulation. We have analysed whether the interleukin 6 signal transducer gp130 dependent on receptor-associated Jak kinases. By using chimaeric system we found that mutants lack box1 therefore are not capable activating activator transcription (STAT) proteins still endocytosed efficiently. A with recently identified dileucine motif being replaced two alanine residues was efficiently internalized but recruiting STATs. Furthermore an antagonistic antibody inhibits signalling all interleukin-6-type cytokines via as agonistic one activates Jak/STAT pathway. Our findings suggest endocytosis signal-independent.