Assessment of roles for the rho-specific guanine nucleotide dissociation inhibitor Ly-GDI in platelet function: A spatial systems approach

Anh T P Ngo, Marisa L D Thierheimer, Ozgun Babur, Anne D. Rocheleau, Tao Huang, Jiaqing Pang, Rachel A. Rigg, Annachiara Mitrugno, Dan Theodorescu, Julja Burchard, Xiaolin Nan, Emek Demir, Owen McCarty, Joseph Aslan

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

On activation at sites of vascular injury, platelets undergo morphological alterations essential to hemostasis via cytoskeletal reorganizations driven by the Rho GTPases Rac1, Cdc42, and RhoA. Here we investigate roles for Rho-specific guanine nucleotide dissociation inhibitor proteins (RhoGDIs) in platelet function. We find that platelets express two RhoGDI family members, RhoGDI and Ly-GDI. Whereas RhoGDI localizes throughout platelets in a granule-like manner, Ly-GDI shows an asymmetric, polarized localization that largely overlaps with Rac1 and Cdc42 as well as microtubules and protein kinase C (PKC) in platelets adherent to fibrinogen. Antibody interference and platelet spreading experiments suggest a specific role for Ly-GDI in platelet function. Intracellular signaling studies based on interactome and pathways analyses also support a regulatory role for Ly-GDI, which is phosphorylated at PKC substrate motifs in a PKC-dependent manner in response to the platelet collagen receptor glycoprotein (GP) VI-specific agonist collagen-related peptide. Additionally, PKC inhibition diffuses the polarized organization of Ly-GDI in spread platelets relative to its colocalization with Rac1 and Cdc42. Together, our results suggest a role for Ly-GDI in the localized regulation of Rho GTPases in platelets and hypothesize a link between the PKC and Rho GTPase signaling systems in platelet function.

Original languageEnglish (US)
Pages (from-to)C527-C536
JournalAmerican Journal of Physiology - Cell Physiology
Volume312
Issue number4
DOIs
StatePublished - Apr 7 2017

Keywords

  • D4-GDI
  • Hemostasis
  • Ly-GDI
  • Rho GTPases
  • RhoGDI2

ASJC Scopus subject areas

  • Physiology
  • Cell Biology

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