Figure 5. Tyrosine phosphorylation and ageing arteries.

A, Src kinase activity, assessed by immunoblot analysis of total compared to Tyr⁴¹⁶ phosphorylation, was increased in old compared to young (yng) tail arteries. Arteries were processed using the single lysis approach and a representative blot is presented. B, tyrosine phosphorylation of VE‐cadherin in old and young aortas was assessed by immunoprecipitation of tyrosine‐phosphorylated proteins followed by immunoblots for VE‐cadherin. This approach was performed on TTX‐soluble (TTX) and TTX‐insoluble (SDS) fractions, obtained using the sequential lysis approach. Representative blots for old and young arteries are presented. Tyrosine phosphorylation was detected in the 115 kDa but not 140 kDa VE‐cadherin species, and levels of tyrosine‐phosphorylated 115 kDa protein were increased in old compared to young aortas.