Lymphocyte-specific protein 1 (LSP1)

Lymphocyte-specific protein 1 (LSP1) is an intracellular F-actin binding protein highly expressed in immune cells including lymphocytes, neutrophils, monocytes, macrophages, and certain endothelial cells[3][4][5][6]. It plays a critical role in regulating the actin cytoskeleton, affecting immune cell migration, adhesion, podosome formation, and mechanosensory oscillations necessary for cell motility and immune responses[1][3][6]. LSP1 interacts with actin, myosin IIA, and several regulators of myosin contractility, modulating the structure and function of the actomyosin cortex, especially in macrophages[1]. It is a key substrate for protein kinase C and MAPKAP kinase 2, linking extracellular signals to cytoskeletal changes[2]. Its expression is specific to leukocytes and absent in non-hematopoietic tissues[2]. LSP1 is relevant in various diseases, including hematologic malignancies (as a marker), inflammatory disorders, and immune deficiencies linked to neutrophil dysfunction[2]. While crucial for immune cell physiology, LSP1 is not currently recognized as a direct therapeutic target or druggable protein (such as a receptor or enzyme)[3][4].

Other names

WP34pp5247 kDa actin-binding protein52 kDa phosphoproteinlymphocyte-specific antigen WP34F-actin-binding and cytoskeleton-associated proteinleufactin (leukocyte F-actin-binding protein)leukocyte-specific protein 1