Multiple Allostery In The Regulation Of PDGFR Beta Kinase Activities

Platelet derived growth factor receptor beta(PDGFR?)and colony stimulating factor 1 receptor(CSF1R)belong to type III receptor tyrosine kinases(RTK).All of them are constitute of an extracellular domain,a single-pass transmembrane domain,an intracellular juxtamembrane segment(JM),a kinase domain splatted apart by a not-well characterized insert(KI),and a c-terminal tail.These receptors regulate important biological processes,including cell proliferation,differentiation and migration.Dysregulation of PDGFR? is associated with cardiovascular and fibrosis diseases,while mutations of CSF1 R could cause malfunctions of microglia and demyelination of neurons in Hereditary Diffuse Leukoencephalopathy with Spheroids(HDLS).Thus,it is important to understand the precise regulation of their kinase activities under physiological conditions.Early biochemical and structural studies of these receptors laid the foundation for understanding the regulation and activation mechanism of these receptor kinases.Early studies demonstrated that these kinases were autoinhibited by their juxtamembrane segments and were activated by transphosphorylation.However,missing gaps were revealed in re-inspection of the concepts and experiments on the regulation of these receptors.Herein,we used chemical cross-linking mass spectrometry(CXMS),structure-based mutagenesis,Rosetta and immunoblotting to explore the regulation of PDGFR? kinase activity.We provided evidences that multiple allostery,including the transactivating dimerization,autoinhibition by kinase insert,and inactive dimerization,were involved in the regulation of these kinases.Moreover,we found the linkage between the mutations of CSF1 R in HDLS and the impaired regulatory of the kinase.