Characterization and cytoskeletal association of a major cell surface glycoprotein, GP 140, in human neutrophils.

Abstract

The binding of specific ligands to neutrophil cell surface receptors and the association of these receptors with the cytoskeleton may represent an essential step in activation. To identify surface proteins that are linked to the cytoskeleton during activation, neutrophil l25l-surface labeled plasma membranes were extracted with Triton X-100, and the soluble and insoluble (cytoskeleton) fractions analyzed by SDS-PAGE and autoradiography. The major cell surface proteins recruited to the cytoskeleton after activation with Con A, FMLP, zymosan-activated serum, or immune complexes possessed a relative molecular mass in the range of 80 to 13 kD. In addition to these proteins, WGA stimulates the recruitment of a 140-kD protein (GP 140) (RBC) band 4.1 and shows strong cross-reactivity with RBC anti-band 4.1 antibody. Phosphorylation of cytoskeletal proteins like 4.1 may be involved in the regulation of interactions between GP 140 and the actin-containing cytoskeleton. Unlike the C3bi receptor, GP 140 is a major surface component of unactivated PMNs, has no stoichiometrically related 95-kD subunit, and has two isoforms with pIs in the range of 6.4 to 6.6. Under conditions that result in an increased expression of the C3bi receptor (such as treatment with the Ca2" ionophore A23187), the amount of GP 140 on the PMN cell surface appears to be significantly reduced. The interaction of GP 140 with the cytoskeleton during activation suggests that GP 140 may play an important role in neutrophil functional responses. IntroductionThe association of PMN cell surface membrane proteins with the cytoskeleton is essential for processes such as shape change,

In Vitro Methods in the Study of Viral and Prion Permeability Across the Blood–Brain Barrier

“…Internalization is not clatharin dependent but does bind to cytoskeletal elements. This is consistent with WGA also binding to cytoskeletalanchored glycoproteins in various types of cells (Kalomiris and Bourguignon, 1988;Lehto and Virtanen, 1983;Mehta et al, 1999;Suchard and Boxer, 1989) and altering F-actin (Sjolander and Magnusson, 1988). Uptake is energy dependent and partially inhibited by potassium.…”

Binding of Cryptococcus neoformans by human cultured macrophages. Requirements for multiple complement receptors and actin.

“…Treatment with either trypsin or human leukocyte elastase has been shown to cleave CR1, but not CR3, on activated human PMN as measured by FACS scanning (20,32). In preliminary studies in our laboratory, we have found that elas- (36,37). Moreover, a subset of plasma membrane CR3 has recently been described that appears to be involved in phagocytosis of particles by several different receptors including CR1 and FcR.…”

Association of the crosslinked IgE receptor with the membrane skeleton is independent of the known signaling mechanisms in rat basophilic leukemia cells.

“…However, crosslinking of cell surface receptors by antibody on B cells (Braun et al, 1982;Woda and McFadden, 1983;Woda and Woodin, 1984), T leukemic cells (Marano et al, 1989), and neutrophils (Jack et al, 1986), as well as lectin-induced receptor crosslinking on neutrophils (Suchard and Boxer, 1989) and PC12 pheochromocytoma cells (Vale and Shooter, 1982), does lead to receptor detergent-insolubility even if the assays are performed at 4°C. Although not measured in any of these cases, it is unlikely that any enzyme-based signaling mechanisms would be active at 40C.…”