BIN2 orchestrates platelet calcium signaling in thrombosis and thrombo-inflammation
Julia Volz, Charly Kusch, Sarah Beck, Michael Popp, Timo Vögtle, Mara Meub, Inga Scheller, Hannah S. Heil, Julia Preu, Michael K. Schuhmann, Katherina Hemmen, Thomas Premsler, Albert Sickmann, Katrin G. Heinze, David Stegner, Guido Stoll, Attila Braun, Markus Sauer, Bernhard Nieswandt
Julia Volz, Charly Kusch, Sarah Beck, Michael Popp, Timo Vögtle, Mara Meub, Inga Scheller, Hannah S. Heil, Julia Preu, Michael K. Schuhmann, Katherina Hemmen, Thomas Premsler, Albert Sickmann, Katrin G. Heinze, David Stegner, Guido Stoll, Attila Braun, Markus Sauer, Bernhard Nieswandt
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Research Article Cell biology Hematology

BIN2 orchestrates platelet calcium signaling in thrombosis and thrombo-inflammation

Abstract

Store-operated Ca2+ entry (SOCE) is the major route of Ca2+ influx in platelets. The Ca2+ sensor stromal interaction molecule 1 (STIM1) triggers SOCE by forming punctate structures with the Ca2+ channel Orai1 and the inositol trisphosphate receptor (IP3R), thereby linking the endo-/sarcoplasmic reticulum to the plasma membrane. Here, we identified the BAR domain superfamily member bridging integrator 2 (BIN2) as an interaction partner of STIM1 and IP3R in platelets. Deletion of platelet BIN2 (Bin2fl/fl,Pf4-Cre mice) resulted in reduced Ca2+ store release and Ca2+ influx in response to all tested platelet agonists. These defects were a consequence of impaired IP3R function in combination with defective STIM1-mediated SOC channel activation, while Ca2+ store content and agonist-induced IP3 production were unaltered. This severely defective Ca2+ signaling translated into impaired thrombus formation under flow and a protection of Bin2fl/fl,Pf4-Cre mice in models of arterial thrombosis and stroke. Our results establish BIN2 as a central regulator of platelet activation in thrombosis and thrombo-inflammatory disease settings.

Authors

Julia Volz, Charly Kusch, Sarah Beck, Michael Popp, Timo Vögtle, Mara Meub, Inga Scheller, Hannah S. Heil, Julia Preu, Michael K. Schuhmann, Katherina Hemmen, Thomas Premsler, Albert Sickmann, Katrin G. Heinze, David Stegner, Guido Stoll, Attila Braun, Markus Sauer, Bernhard Nieswandt

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Figure 1

BIN2 is highly expressed in human and mouse platelets.

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BIN2 is highly expressed in human and mouse platelets. (A) Western blot ...
(A) Western blot analysis of BIN2 expression in human tissue lysates; GAPDH was used as loading control. (B) IP of BIN2 was performed with human platelet lysates using an anti-BIN2 antibody. BIN2, STIM1, and RhoA were detected by Western blot. Representative result of 3 independent experiments. Lane 4 was run on the same gel as 1 to 3, but the lanes were noncontiguous. (C) Recombinant GST-tagged STIM1 C-tail incubated with recombinant BIN2 protein. Pulldown of the GST-tagged STIM1 was performed, and the resulting fractions were analyzed by SDS page and silver staining. (D) Western blot analysis of BIN2 expression in the indicated tissue lysates of WT and Bin2–/– mice with GAPDH as loading control. See complete unedited blots in the supplemental material.