Schematic of phagocytic cell engulfing an apoptotic cell as mediated by recognition of phosphatidylserine (PS) signals.

Schematic of phagocytic cell engulfing an apoptotic cell as mediated by recognition of phosphatidylserine (PS) signals.

Ismail et al. characterized Tctex-1, a novel binding partner of kidney injury molecule-1 (KIM-1), and described the role both proteins have in efferocytosis, the phagocytosis of apoptotic cells. Efferocytosis is an important function in tissue repair, reducing inflammation and abnormal autoimmune responses. KIM-1 is a phosphatidylserine (PS) receptor and PS is a well-known identifier of apoptotic cells. The physical and functional interactions between Tctex-1 and KIM-1 were examined in proximal tubular epithelial cells (PTECs) which can act as amateur phagocytes. A previously unknown role for Tctex-1 in KIM-1-mediated efferocytosis in PTECs was described. Efferocytosis requires re-organization of the actin and microtubule networks, prompting the authors to examine actin cytoskeletal dynamics and the potential role of RhoA and Rac1 in efferocytosis mediated by Tctex-1/KIM-1. Notably, neither RhoA nor Rac1 activities were regulated by Tctex-1 during KIM-1-dependent efferocytosis in PTECs. These data suggested the unexpected hypothesis that non-canonical pathways not involving RhoA and Rac1 are utilized by Tctex-1. Cytoskeleton’s rhodamine-phalloidin, RhoA and Rac1 G-LISA activation assay kits, and Total RhoA ELISA (Cat. # PHDR1, BK124, BK128, BK150, respectively) were essential reagents in this study, the first to describe the physical and functional roles of Tctex-1 in KIM-1-dependent efferocytosis in kidney cells.

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Products used in this citation:

Rhodamine Phalloidin (Cat. # PHDR1)

RhoA G-LISA Activation Assay Kit (Colorimetric format) (Cat. # BK124)

Rac1 G-LISA Activation Assay Kit (Colorimetric Based) (Cat. # BK128)

Total RhoA ELISA (Cat. # BK150)

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