Intermediate Filament and Associated Proteins in Heart Purkinje Fibers: A Membrane-Myofibril Anchored Cytoskeletal System

A Mr 60,000 protein of the axonal cortical cytoplasm, which is recognized by a novel monoclonal antibody, is described. The antibody, DR1, was produced by immunizing mice with a soluble extract of bovine brain membranes that is enriched in known membrane cytoskeletal proteins. DR1 recognizes a Mr 60,000 protein in this extract. Immunofluorescence and subcellular fractionation reveal that the protein is primarily located in axons, where it appears to form a thick lining to the axolemma. Operationally, this Mr 60,000 protein is defined as a cytoskeleton-associated peripheral membrane protein. It is solubilized from brain membranes only under harsh conditions (0.1 M-NaOH), but not with KI (0.8 M) or Triton X-100 (1%). It is present at higher levels in the central nervous system than in peripheral nerves that have been examined. The Mr 60,000 protein copurifies with neurofilaments through cycles of assembly and disassembly. It does not appear to react with the anti-IFA antibody, suggesting that it is not a member of the intermediate filament class of proteins. This Mr 60,000 protein, which we designate A60, is distinct from other known neurofilament-associated proteins, including the Mr 60,000 protein alpha-internexin and the Mr 58,000 intermediate filament protein peripherin. A60 is suggested as being a previously unrecognized component of the axonal cortical cytoskeleton.

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Existence of trichohyalin-keratohyalin hybrid granules: Co-localization of two major intermediate filament-associated proteins in non-follicular epithelia

Differentiation ◽

10.1046/j.1432-0436.1994.5810065.x ◽

1994 ◽

Vol 58 (1) ◽

pp. 65-75 ◽

Cited By ~ 41

Author(s):

Motomu Manabe ◽

W. Michael O'Guin

Keyword(s):

Intermediate Filament ◽

Associated Proteins

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Expression of intermediate filament-associated proteins paranemin and synemin in chicken development.

The Journal of Cell Biology ◽

10.1083/jcb.97.6.1860 ◽

1983 ◽

Vol 97 (6) ◽

pp. 1860-1874 ◽

Cited By ~ 59

Author(s):

M G Price ◽

E Lazarides

Keyword(s):

Smooth Muscle ◽

Intermediate Filament ◽

Muscle Cells ◽

Myocardial Cells ◽

Adult Chicken ◽

Intermediate Filament Proteins ◽

Adult Muscle ◽

Associated Proteins ◽

Visceral Smooth Muscle ◽

Chicken Development

The expression of two intermediate filament-associated proteins, paranemin (280,000 mol wt) and synemin (230,000 mol wt), was investigated with respect to the expression of two core intermediate filament proteins, desmin and vimentin, in various embryonic and adult chicken muscle and nonmuscle cells. All developing muscle cells, regardless of their type, simultaneously express desmin, vimentin, paranemin, and synemin. However, a difference is observed in the expression of paranemin in adult muscle. This protein is removed during differentiation of both fast and slow skeletal muscle, visceral smooth muscle, and the smooth muscle of muscular arteries, but remains in mature myocardial cells, cardiac conducting fibers, and the smooth muscle cells of elastic arteries. Some of these cells express vimentin, others desmin, and still others a mixture of the two. On the other hand, synemin is expressed in all the above types of adult muscle cells except myocardial cells. Adult myocardial cells also lack vimentin, and its presence is gradually reduced after hatching. Since in adult striated muscle all expressed intermediate filament proteins are found predominantly in association with the peripheries of myofibrillar Z discs, these results suggest that a change in the composition of skeletal and cardiac muscle Z discs occurs during chicken development and maturation. Erythrocytes that express synemin and vimentin do not express paranemin, while both embryonic and adult Schwann cells co-express paranemin and vimentin, but not synemin. Endothelial cells of muscular vessels express paranemin, while those of elastic vessels do not, and neither contains synemin. Paranemin and synemin are not expressed in neurons, epithelial, and most glial cells, suggesting that these two polypeptides are expressed only in conjunction with desmin or vimentin. These results suggest that the composition of intermediate filaments changes during chicken development, not only with respect to their core subunit proteins but also with respect to two associated polypeptides, particularly in muscle cells.

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Intermediate filament-associated proteins

Current Opinion in Cell Biology ◽

10.1016/0955-0674(91)90168-x ◽

1991 ◽

Vol 3 (1) ◽

pp. 75-81 ◽

Cited By ~ 70

Author(s):

Roland Foisner ◽

Gerhard Wiche

Keyword(s):

Intermediate Filament ◽

Associated Proteins

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The cytoskeletal system of nucleated erythrocytes. I. Composition and function of major elements.

The Journal of Cell Biology ◽

10.1083/jcb.93.3.828 ◽

1982 ◽

Vol 93 (3) ◽

pp. 828-828 ◽

Cited By ~ 35

Author(s):

W D Cohen ◽

D Bartelt ◽

R Jaeger ◽

G Langford ◽

I Nemhauser

Keyword(s):

Cell Shape ◽

Major Elements ◽

Erythrocyte Morphology ◽

Thin Sections ◽

Marginal Band ◽

Associated Proteins ◽

Cross Bridges ◽

And Function ◽

Cytoskeletal System

We have studied the dogfish erythrocyte cytoskeletal system, which consists of a marginal band of microtubules (MB) and trans-marginal band material (TBM). The TBM appeared in whole mounts as a rough irregular network and in thin sections as a surface-delimiting layer completely enclosing nucleus and MB. In cells incubated at 0 degrees C for 30 min or more, the MB disappeared but the TBM remained. MB reassembly occurred with rewarming, and was inhibited by colchicine. Flattened elliptical erythrocyte morphology was retained even when MBs were absent. Total solubilization of MB and TBM at low pH, or dissolution of whole anucleate cytoskeletons, yielded components comigrating with actin, spectrin, and tubulin standards during gel electrophoresis. Mass-isolated MBs, exhibiting ribbonlike construction apparently maintained by cross-bridges, contained four polypeptides in the tubulin region of the gel. Only these four bands were noticeably increased in the soluble phase obtained from cells with 0 degrees C-disassembled MBs. The best isolated MB preparations contained tubulin but no components comigrating with high molecular weight microtubule-associated proteins, spectrin, or actin. Actin and spectrin therefore appear to be major TBM constituents, with tubulin localized in the MB. The results are interpreted in terms of an actin- and spectrin-containing subsurface cytoskeletal layer (TBM), related to that of mammalian erythrocytes, which maintains cell shape in the absence of MBs. Observations on abnormal pointed erythrocytes containing similarly pointed MBs indicate further that the MB can deform the TBM from within so as to alter cell shape. MBs may function in this manner during normal cellular morphogenesis and during blood flow in vivo.

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Intermediate filament and associated proteins in the human heart: An immunofluorescence study of normal and pathological hearts

European Heart Journal ◽

10.1093/eurheartj/5.suppl_f.231 ◽

1984 ◽

Vol 5 (suppl F) ◽

pp. 231-241 ◽

Cited By ~ 25

Author(s):

L.-E. Thornell ◽

B. Johansson ◽

A. Eriksson ◽

V.-P. Lehto ◽

I. Virtanen

Keyword(s):

Intermediate Filament ◽

Human Heart ◽

Immunofluorescence Study ◽

Associated Proteins

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The cystoskeleton of unstimulated blood platelets: structure and composition of the isolated marginal microtubular band

Journal of Cell Science ◽

10.1242/jcs.78.1.1 ◽

1985 ◽

Vol 78 (1) ◽

pp. 1-22 ◽

Cited By ~ 1

Author(s):

D.M. Kenney ◽

R.W. Linck

Keyword(s):

Blood Platelets ◽

Amorphous Material ◽

Structural Units ◽

Microtubule Associated Proteins ◽

Major Structural Component ◽

Associated Proteins ◽

Amorphous Surface ◽

Cytoskeletal System ◽

Brain Tubulin ◽

Dimensional Electrophoresis

Detergent-insoluble, marginal microtubular band (MB) cytoskeletons were isolated from unstimulated blood platelets after pretreatment with glycerol or with Taxol. MB cytoskeletons retained the shape of intact platelets and behaved in suspension as coherent structural units. The major structural component was a continuous coil of long microtubule(s), often with granular/amorphous material present in the centre; few typical actin filaments were observed. The coiled microtubules often had an amorphous surface coating, but no discrete inter-microtubule bridges were seen. Tubulin and actin (identified by immunochemical staining) were major polypeptides. None of the minor (greater than 10) polypeptide components comigrated with high molecular weight microtubule-associated proteins in brain tubulin. A novel polypeptide, resolved by two-dimensional electrophoresis and designated IEF-51K, was present in MB cytoskeletons in amounts approximately equivalent to each of the tubulin polypeptides. Evidence suggests that IEF-51K is a distinct, previously undescribed component of the platelet cytoskeletal system.

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