Reelin is a platelet protein and functions as a positive regulator of platelet spreading on fibrinogen.
Abnormalities of platelet functions have been linked to reelin-impaired neuronal disorders. However, little attention has been given to understanding the interplay between reelin and platelet. In this study, reelin was found to present in the human platelets and megakaryocyte-like leukemic cells. Reelin-binding assays revealed that extracellular reelin can interact with platelets through the receptor belonging to the low density lipoprotein receptor gene family. The reelin-to-platelet interactions enhance platelet spreading on fibrinogen concomitant with the augmentation of lamellipodia formation and F-actin bundling. In contrast, reelin has no effect on integrin alphaIIbbeta3 activation and agonist-induced platelet aggregation. Molecular analysis revealed that the up-regulation of Rac1 activity and the inhibition of protein kinase C delta-Thr505 phosphorylation are important for reelin-mediated enhancement of platelet spreading on fibrinogen. These findings demonstrate for the first time that reelin is present in platelets and the reelin-to-platelet interactions play a novel role in platelet signaling and functions.
Tseng
Wei-Lien
WL
Graduate Institute of Biomedical Sciences, Chang Gung University, Kweishan, Taoyuan 333, Taiwan, ROC.
Huang
Chien-Ling
CL
Chong
Kowit-Yu
KY
Liao
Chang-Huei
CH
Stern
Arnold
A
Cheng
Ju-Chien
JC
Tseng
Ching-Ping
CP
D001792:Blood Platelets / Q000378:metabolism / Q000502:physiology*; D015816:Cell Adhesion Molecules, Neuronal / Q000097:blood / Q000502:physiology*; D045744:Cell Line, Tumor; D002465:Cell Movement; D016326:Extracellular Matrix Proteins / Q000097:blood / Q000502:physiology*; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D009419:Nerve Tissue Proteins / Q000097:blood / Q000502:physiology*; D010974:Platelet Aggregation; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000819:agonists / Q000378:metabolism; D000091042:Reelin Protein; D012697:Serine Endopeptidases / Q000097:blood / Q000502:physiology*
D015816:Cell Adhesion Molecules, Neuronal; D016326:Extracellular Matrix Proteins; D009419:Nerve Tissue Proteins; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D000091042:Reelin Protein; D005340:Fibrinogen; C000717127:RELN protein, human; D012697:Serine Endopeptidases