Novel role for p21-activated kinase 2 in thrombin-induced monocyte migration
Authors: Nikhlesh K Singh
Gadiparthi N Rao
Ravisekhar Gadepalli
Sivareddy Kotla
Mark R Heckle
Shailendra K Verma
Journal: Journal of Biological Chemistry (2013)
Discipline: BIOLOGY & BIOCHEMISTRY
Keywords: G Protein-coupled Receptors (GPCRs); Inflammation; Macrophages; Migration; Signaling.
Affiliations: From the Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163.

Abstract:  To understand the role of thrombin in inflammation, we tested its effects on migration of THP-1 cells, a human monocytic cell line. Thrombin induced THP-1 cell migration in a dose-dependent manner. Thrombin induced tyrosine phosphorylation of Pyk2, Gab1, and p115 RhoGEF, leading to Rac1- and RhoA-dependent Pak2 activation. Downstream to Pyk2, Gab1 formed a complex with p115 RhoGEF involving their pleckstrin homology domains. Furthermore, inhibition or depletion of Pyk2, Gab1, p115 RhoGEF, Rac1, RhoA, or Pak2 levels substantially attenuated thrombin-induced THP-1 cell F-actin cytoskeletal remodeling and migration. Inhibition or depletion of PAR1 also blocked thrombin-induced activation of Pyk2, Gab1, p115 RhoGEF, Rac1, RhoA, and Pak2, resulting in diminished THP-1 cell F-actin cytoskeletal remodeling and migration. Similarly, depletion of Gα12 negated thrombin-induced Pyk2, Gab1, p115 RhoGEF, Rac1, RhoA, and Pak2 activation, leading to attenuation of THP-1 cell F-actin cytoskeletal remodeling and migration. These novel observations reveal that thrombin induces monocyte/macrophage migration via PAR1-Gα12-dependent Pyk2-mediated Gab1 and p115 RhoGEF interactions, leading to Rac1- and RhoA-targeted Pak2 activation. Thus, these findings provide mechanistic evidence for the role of thrombin and its receptor PAR1 in inflammation. 

Retracted: Yes

PubPeer comments:
 Figures 4C, 5C, 10D: * Green and pink boxes: two sets of panels appear to look very similar. The labels suggest that these should have shown different photos. ![file] , 
 Necessary action is being taken. , 
 One more repetition. Figure 2C and Figure 8A ![file] , 
 Retraction, April 2022: https: www.jbc.org article S0021-9258(22)00319-2 fulltext  This article has been withdrawn by the authors. The Journal states that the immunoblots corresponding to u2018Rac1u2019 in figure 4B and 4H were duplicated. The immunoblots corresponding to u2018beta-Tubulinu2019 in figure 4B and u2018Pak2u2019 in figure 5E were duplicated. Possible micrograph reuse for u2018RhoA ASO3 + Thrombinu2019 panel in figure 4C and u2018Control ASOu2019 panel in figure 10D. Additional potential reuse in u2018Pak2 ASO2 + Thrombinu2019 panel in figure 5C and u2018G-alpha-qASO2u2019 panel in figure 10D. Possible reuse in immunoblot panels for u2018GTP-RhoAu2019 in figure 4E and u2018GTP-Rac1u2019 in figure 10J. Additional potential reuse between micrograph panels u2018SCH79797+Thrombinu2019 in figure 8A and u2018Control ASOu2019 in figure 2C. There was possible image reuse between immunoblots u2018beta-Tubulinu2019 panel in figure 7A and u2018Pak2u2019 panel in figure 7F. Finally, there was possible image reuse for u2018PY20u2019 immunoblot panel in figures 7D and 9E, which represent different experimental conditions. Due to these immunoblot and image duplications, the authors wish to withdraw this article. , 
 Here are the additional duplications mentioned in the Retraction Notice.  *The Journal states that the immunoblots corresponding to u2018Rac1u2019 in figure 4B and 4H were duplicated. The immunoblots corresponding to u2018beta-Tubulinu2019 in figure 4B and u2018Pak2u2019 in figure 5E were duplicated.* Marked here with orange boxes: ![file] ,