PubMed Health⌕ Search

PubMed · 2660673

Cell membrane and volume changes during red cell development and aging.

Abstract

This paper provides a summary of our understanding of cell membrane and volume changes during red cell development and aging. Cytoskeletal structures which include microtubules and microfilaments appear to play key roles in the genesis of the anucleate reticulocyte from its nucleated precursor cell, as well as in the early stages of reticulocyte development. The maturation of reticulocyte into red cell is accompanied by marked changes in cell shape and extensive remodeling of the membrane skeleton, resulting in the mature red cell acquiring a highly deformable yet remarkably stable membrane. The volume and cell density heterogeneity seen for circulating red cells also appears to be the result of the membrane changes that occur during reticulocyte maturation. Following its genesis from reticulocyte, the mature red cell undergoes further membrane and volume changes during its life span of 120 days. While it is clear that surface area loss, decrease in cell volume and cell surface modifications leading to binding of immunoglobulins accompany red cell aging, the cardinal cellular modification responsible for the removal of senescent red cells from the circulation is yet to be defined.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

N Mohandas, W Groner. 1989. Cell membrane and volume changes during red cell development and aging.. https://doi.org/10.1111/j.1749-6632.1989.tb22423.x

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Role of transglutaminase II in retinoic acid-induced activation of RhoA-associated kinase-2.

Transamidation is a post-translational modification of proteins mediated by tissue transglutaminase II (TGase), a GTP-binding protein, participating in signal transduction pathways as a non-conventional G-protein. Retinoic acid (RA), which is known to have a role in cell differentiation, is a potent activator of TGASE: The activation of TGase results in increased transamidation of RhoA, which is inhibited by monodansylcadaverine (MDC; an inhibitor of transglutaminase activity) and TGaseM (a TGase mutant lacking transglutaminase activity). Transamidated RhoA functions as a constitutively active G-protein, showing increased binding to its downstream target, RhoA-associated kinase-2 (ROCK-2). Upon binding to RhoA, ROCK-2 becomes autophosphorylated and demonstrates stimulated kinase activity. The RA-stimulated interaction between RhoA and ROCK-2 is blocked by MDC and TGaseM, indicating a role for transglutaminase activity in the interaction. Biochemical effects of TGase activation, coupled with the formation of stress fibers and focal adhesion complexes, are proposed to have a significant role in cell differentiation.

Cytoskeleton↗

Eccentric exercise-induced injuries to contractile and cytoskeletal muscle fibre components.

Exercise involving lengthening of an activated muscle can cause injury. Recent reports documented the mechanics of exercise-induced muscle injury as well as physiological and cellular events and manifestations of injury. Loss of the cytoskeletal protein desmin and loss of cellular integrity as evidenced by sarcolemmal damage occur early during heavy eccentric exercise. These studies indicate that the earliest events in muscle injury are mechanical in nature, while later events indicate that it may be more appropriate to conclude that intense exercise initiates a muscle remodeling process. We conclude that muscle injury after eccentric exercise is differently severe in muscles with different architecture, is fibre type-specific, primarily because of fibre strain in the acute phase, and is exacerbated by inflammation after the initial injury.

Cytoskeleton↗

Phosphatidylinositol 3-kinase mediates integrin-dependent NF-kappaB and MAPK activation through separate signaling pathways.

Integrin-mediated signals play an important but poorly understood role in regulating many leukocyte functions. In monocytes and monocytic leukemia cells, beta1 integrin-mediated adhesion results in a strong induction of immediate-early genes that are important in inflammation. To investigate the signaling pathways from integrins in monocytic cells, THP-1 cells were stimulated via beta1 integrins by binding to fibronectin and by crosslinking the integrins with specific monoclonal antibodies. The involvement of MAPK and PI 3-K on nuclear factor kappaB (NF-kappaB) activation was then analyzed. We found that integrins activated both NF-kappaB and MAPK in a PI 3-K-dependent manner, as wortmannin and LY294002 blocked these responses. However, the specific MEK inhibitor PD98059 did not prevent integrin-mediated NF-kappaB activation. In contrast, a dominant negative mutant of Rac completely prevented NF-kappaB activation, but it did not affect MAPK activation. These results indicate that integrin signaling to NF-kappaB is not mediated by the MAPK pathway, but rather by the small GTPase Rac. In addition, a dominant negative form of Rho augmented NF-kappaB activation and blocked MAPK activation, implying that these two pathways are in competition with each other. These data suggest that integrins activate different signaling pathways in monocytic cells. One uses PI 3-K and Rac to activate NF-kappaB, while the other uses PI 3-K, MEK, and MAPK to activate other nuclear factors, such as Elk-1.

Cytoskeleton↗