Ligation of cell
surface-associated glucose-regulated protein 78 by
receptor-recognized forms of alpha 2-macroglobulin: activation of
p21-activated protein kinase-2-dependent signaling in murine
peritoneal macrophages.
Misra UK, Sharma T, Pizzo SV. Ligation
of cell surface-associated glucose-regulated protein 78 by
receptor-recognized forms of alpha 2-macroglobulin: activation of
p21-activated protein kinase-2-dependent signaling in murine
peritoneal macrophages. Department of Pathology, Duke University
Medical Center, Durham, NC 27710, USA.
Previous studies of the plasma proteinase inhibitor
alpha2-macroglobulin(alpha2M) demonstrated that alpha2M-proteinase
complexes (alpha2M*) modulateimmune responses and promotes
macrophage locomotion and chemotaxis. Alpha2M*binds to cell
surface-associated glucose-regulated protein 78 (GRP78),
whichactivates downstream signaling events. The role of
p21-activated protein kinase-1and -2 (PAK-1 and -2) in promoting
cellular motility is well documented. In thecurrent study, we
examined the ability of alpha2M* to activate PAK-1 and PAK-2.Upon
macrophage stimulation with alpha2M*, PAK-2 is autophosphorylated,
resultingin increased kinase activity; however, PAK-1 is negligibly
affected.