Assessment of roles for the Rho-specific guanine nucleotide dissociation inhibitor Ly-GDI in platelet function: a spatial systems approach.
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.
Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon.
Anh T P
AT
Ngo
Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon.|School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, Oregon; and.
Marisa L D
ML
Thierheimer
Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon.|Computational Biology Program, Oregon Health & Science University, Portland, Oregon.
Özgün
Ö
Babur
Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon.
Anne D
AD
Rocheleau
Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon.
Tao
T
Huang
Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon.
Jiaqing
J
Pang
Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon.
Rachel A
http://orcid.org/0000-0003-4188-1935
RA
Rigg
Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon.
Annachiara
A
Mitrugno
Department of Surgery, Department of Pharmacology, and Comprehensive Cancer Center University of Colorado, Aurora, Colorado.
Dan
D
Theodorescu
Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon.
Julja
J
Burchard
Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon.
Xiaolin
X
Nan
Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon.|Computational Biology Program, Oregon Health & Science University, Portland, Oregon.
Emek
E
Demir
Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon.|Department of Cell, Developmental & Cancer Biology, Oregon Health & Science University, Portland, Oregon.|Division of Hematology & Medical Oncology, Oregon Health & Science University, Portland, Oregon.
Owen J T
OJ
McCarty
Knight Cardiovascular Institute, School of Medicine, Oregon Health & Science University, Portland, Oregon; aslanj@ohsu.edu.
Joseph E
http://orcid.org/0000-0002-8873-0387
JE
Aslan
D001777:Blood Coagulation / Q000502:physiology*; D001792:Blood Platelets / Q000502:physiology*; D002478:Cells, Cultured; D006487:Hemostasis / Q000502:physiology; D006801:Humans; D015539:Platelet Activation / Q000502:physiology*; D010973:Platelet Adhesiveness / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D013347:Subcellular Fractions / Q000378:metabolism; D062949:rho Guanine Nucleotide Dissociation Inhibitor beta / Q000378:metabolism*; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors / Q000378:metabolism*
C569658:ARHGDIB protein, human; D062949:rho Guanine Nucleotide Dissociation Inhibitor beta; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors
D4-GDI; Ly-GDI; Rho GTPases; RhoGDI2; hemostasis