Erythroid and nonerythroid spectrins

Abstract

Recent developments have contributed important information to understanding the role of spectrins in the RBC membrane skeleton and nonerythroid cells. Many questions can now be framed, informed by structural knowledge of various spectrin subunit types and alternatively spliced variants, that previously could not have been addressed. Their solution in the coming years will likely lead to further advances with direct relevance to biology and medicine.

αII-Spectrin interacts with five groups of functionally important proteins in the nucleus

“…Spectrin is a member of a family of cytoskeletal proteins that are ubiquitous in eukaryotic cells. It was first identified as a major constituent of the erythrocyte membrane cytoskeleton but has since been found in nonerythroid cells in both vertebrates as well as invertebrates (Bennett and Gilligan, 1993;Winkelmann and Forget, 1993;Lux and Palek, 1995;Goodman et al, 1995;Gascard and Mohandas, 2000). In erythrocytes, spectrin forms a submembrane cytoskeletal network that is pivotal for maintaining the structural integrity of the cell membrane and cell shape (Bennett and Gilligan, 1993;Winkelmann and Forget, 1993;Lux and Palek, 1995).…”

“…Structurally, spectrin is a long flexible molecule consisting of a series of repeating units, each of about 106 amino acids which fold into a triple a-helical structure (Winkelmann and Forget, 1993;Bennett and Baines, 2001;Broderick and Winder, 2002). In erythrocytes and in the cytoplasm of nonerythroid cells, spectrin is composed of a heterodimer of aand b-subunits that associate to form tetramers (Winkelmann and Forget, 1993;Bennett and Baines, 2001).…”

“…Structurally, spectrin is a long flexible molecule consisting of a series of repeating units, each of about 106 amino acids which fold into a triple a-helical structure (Winkelmann and Forget, 1993;Bennett and Baines, 2001;Broderick and Winder, 2002). In erythrocytes and in the cytoplasm of nonerythroid cells, spectrin is composed of a heterodimer of aand b-subunits that associate to form tetramers (Winkelmann and Forget, 1993;Bennett and Baines, 2001). Each spectrin subunit also contains nonrepetitive sequences which, along with the spectrin repeats, may play important roles in protein interactions (Winkelmann and Forget, 1993;Bennett and Baines, 2001;Djinovic-Carugo et al, 2002;Young and Kothary, 2005).…”

“…In erythrocytes and in the cytoplasm of nonerythroid cells, spectrin is composed of a heterodimer of aand b-subunits that associate to form tetramers (Winkelmann and Forget, 1993;Bennett and Baines, 2001). Each spectrin subunit also contains nonrepetitive sequences which, along with the spectrin repeats, may play important roles in protein interactions (Winkelmann and Forget, 1993;Bennett and Baines, 2001;Djinovic-Carugo et al, 2002;Young and Kothary, 2005). In the cytoplasm of erythroid and nonerythroid cells, association of spectrin with a number of different proteins, such as actin, ankyrin, CD45, annexin VI, a-catenin and Tes, points to a number of different roles for this protein (De Matteis and Morrow, 2000;Bennett and Baines, 2001;Pradhan et al, 2001;Djinovic-Carugo et al, 2002;Broderick and Winder, 2005;Rotter et al, 2005;Young and Kothary, 2005).…”

Non-erythroid spectrin (fodrin) in cutaneous tumours: diminished in cell membranes, increased in the cytoplasm

“…where it forms the basic constituent of the subplasmalemmal network, commonly known as the membrane skeleton. [2][3][4][5] Biochemical and immunohistochemical studies have shown that spectrin is expressed in all normal keratinocytes, except the fully cornified cells. *'~Î n vivo and in vitro studies have revealed a peripheral, membrane-bound distribution of spectrin in suprabasal epidermal keratinocytes.…”