The deleted in brachydactyly B domain of ROR2 is required for receptor activation by recruitment of Src.
The transmembrane receptor 'ROR2' resembles members of the receptor tyrosine kinase family of signalling receptors in sequence but its' signal transduction mechanisms remain enigmatic. This problem has particular importance because mutations in ROR2 are associated with two human skeletal dysmorphology syndromes, recessive Robinow Syndrome (RS) and dominant acting Brachydactyly type B (BDB). Here we show, using a constitutive dimerisation approach, that ROR2 exhibits dimerisation-induced tyrosine kinase activity and the ROR2 C-terminal domain, which is deleted in BDB, is required for recruitment and activation of the non-receptor tyrosine kinase Src. Native ROR2 phosphorylation is induced by the ligand Wnt5a and is blocked by pharmacological inhibition of Src kinase activity. Eight sites of Src-mediated ROR2 phosphorylation have been identified by mass spectrometry. Activation via tyrosine phosphorylation of ROR2 receptor leads to its internalisation into Rab5 positive endosomes. These findings show that BDB mutant receptors are defective in kinase activation as a result of failure to recruit Src.
Akbarzadeh
Shiva
S
CR-UK Growth Factor Group, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom.
Wheldon
Lee M
LM
Sweet
Steve M M
SM
Talma
Sonia
S
Mardakheh
Faraz Khosravi
FK
Heath
John K
JK
D002460:Cell Line; D006801:Humans; D010766:Phosphorylation; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism*; D057050:Receptor Tyrosine Kinase-like Orphan Receptors; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000378:metabolism*; D013379:Substrate Specificity; D014443:Tyrosine / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism; D000071818:Wnt-5a Protein; D020696:rab5 GTP-Binding Proteins / Q000378:metabolism
D011518:Proto-Oncogene Proteins; D011956:Receptors, Cell Surface; C085389:WNT5A protein, human; D051153:Wnt Proteins; D000071818:Wnt-5a Protein; D014443:Tyrosine; C078717:ROR2 protein, human; D057050:Receptor Tyrosine Kinase-like Orphan Receptors; D016392:Proto-Oncogene Proteins pp60(c-src); D020696:rab5 GTP-Binding Proteins