RhoJ regulates α5β1 integrin trafficking to control fibronectin remodeling during angiogenesis

Ananthalakshmy Sundararaman, Yoko Fukushima, Jim C Norman, Akiyoshi Uemura, Harry Mellor*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

21 Citations (Scopus)
91 Downloads (Pure)


Rho GTPases are master regulators of cell shape and cell movement [1]. The archetypal family members RhoA, Rac1 and Cdc42 arose early in eukaryotic evolution and coordinate a diverse range of cell morphologies and migrations. Evolution of the vertebrates was paralleled by expansion of this family through gene duplication. Emergence of an adaptive immune system and more complex neural systems presented new roles for Rho GTPases, filled by new family members. Cdc42 underwent gene duplication to produce two related proteins – RhoQ and RhoJ [2]. RhoQ is active in neural dynamics; however, RhoJ is highly-expressed in endothelial cells under control of the endothelial-specific promoter ERG [3, 4]. RhoJ is required for angiogenesis [5, 6] and has multiple roles in this process [7, 8]. We recently demonstrated that RhoJ regulates the endosomal trafficking of podocalyxin during angiogenesis to control lumen formation [9]. Here we use vesicle purification and proteomic analysis to identify the endothelial targets of RhoJ-mediated trafficking. We identify α5β1
integrin as a major RhoJ cargo and show that RhoJ regulates the intracellular trafficking of active α5β1 integrin in endothelial cells to repress fibronectin fibrillogenesis. Accordingly, mice lacking RhoJ show deregulated deposition of fibronectin around vessels during developmental angiogenesis. Intriguingly, we show that RhoJ acts in opposition to Cdc42 in this process through competition for a shared partner, PAK3. These studies identify a critical role for RhoJ in matrix remodeling during blood vessel formation and demonstrate a functional interrelationship between RhoJ and its evolutionary parent.
Original languageEnglish
Pages (from-to)P2146-2155
Number of pages16
JournalCurrent Biology
Early online date16 Apr 2020
Publication statusPublished - 8 Jun 2020


  • endothelial
  • Rho GTPase
  • fibrillogenesis
  • angiogenesis
  • integrin
  • intracellular traffic


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