scholarly journals Intermediate filament proteins of digestive organs: physiology and pathophysiology

2017 ◽  
Vol 312 (6) ◽  
pp. G628-G634 ◽  
Author(s):  
M. Bishr Omary
Keyword(s):  
Intermediate Filament ◽  
Protein Targeting ◽  
Current Knowledge ◽  
Aggregate Formation ◽  
Intermediate Filament Proteins ◽  
Nuclear Lamins ◽  
Digestive Organs ◽  
High Throughput Drug Screening ◽  
Disease Mutations ◽  
Current Knowledge Base

Intermediate filament proteins (IFs), such as cytoplasmic keratins in epithelial cells and vimentin in mesenchymal cells and the nuclear lamins, make up one of the three major cytoskeletal protein families. Whether in digestive organs or other tissues, IFs share several unique features including stress-inducible overexpression, abundance, cell-selective and differentiation state expression, and association with >80 human diseases when mutated. Whereas most IF mutations cause disease, mutations in simple epithelial keratins 8, 18, or 19 or in lamin A/C predispose to liver disease with or without other tissue manifestations. Keratins serve major functions including protection from apoptosis, providing cellular and subcellular mechanical integrity, protein targeting to subcellular compartments, and scaffolding and regulation of cell-signaling processes. Keratins are essential for Mallory-Denk body aggregate formation that occurs in association with several liver diseases, whereas an alternate type of keratin and lamin aggregation occurs upon liver involvement in porphyria. IF-associated diseases have no known directed therapy, but high-throughput drug screening to identify potential therapies is an appealing ongoing approach. Despite the extensive current knowledge base, much remains to be discovered regarding IF physiology and pathophysiology in digestive and nondigestive organs.

A cDNA from Drosophila melanogaster encodes a lamin C-like intermediate filament protein

1993 ◽  
Vol 104 (4) ◽  
pp. 1263-1272 ◽  
Author(s):  
C.A. Bossie ◽  
M.M. Sanders
Keyword(s):  
Drosophila Melanogaster ◽  
Intermediate Filament ◽  
Blot Analysis ◽  
Polytene Chromosomes ◽  
Intermediate Filament Protein ◽  
Chromosome 2 ◽  
Cross Hybridization ◽  
Intermediate Filament Proteins ◽  
Nuclear Lamins ◽  
Filament Protein

A novel intermediate filament cDNA, pG-IF, has been isolated from a Drosophila melanogaster embryonic expression library screened with a polyclonal antiserum produced against a 46 kDa cytoskeletal protein isolated from Kc cells. This 46 kDa protein is known to be immunologically related to vertebrate intermediate filament proteins. The screen resulted in the isolation of four different cDNA groups. Of these, one has been identified as the previously characterized Drosophila nuclear lamin cDNA, Dm0, and a second, pG-IF, demonstrates homology to Dm0 by cross hybridization on Southern blots. DNA sequence analysis reveals that pG-IF encodes a newly identified intermediate filament protein in Drosophila. Its nucleotide sequence is highly homologous to nuclear lamins with lower homology to cytoplasmic intermediate filament proteins. pG-IF predicts a protein of 621 amino acids with a predicted molecular mass of 69,855 daltons. In vitro transcription and translation of pG-IF yielded a protein with a SDS-PAGE estimated molecular weight of approximately 70 kDa. It contains sequence principles characteristic of class V intermediate filament proteins. Its near neutral pI (6.83) and the lack of a terminal CaaX motif suggests that it may represent a lamin C subtype in Drosophila. In situ hybridization to polytene chromosomes detects one band of hybridization on the right arm of chromosome 2 at or near 51A. This in conjunction with Southern blot analysis of various genomic digests suggests one or more closely placed genes while Northern blot analysis detects two messages in Kc cells.

scholarly journals Characterisation of neurofilament protein NF70 mRNA from the gastropod Helix aspersa reveals that neuronal and non-neuronal intermediate filament proteins of cerebral ganglia arise from separate lamin-related genes

1995 ◽  
Vol 108 (11) ◽  
pp. 3581-3590 ◽  
Author(s):  
J. Adjaye ◽  
U. Plessmann ◽  
K. Weber ◽  
H. Dodemont
Keyword(s):  
Sequence Analysis ◽  
Intermediate Filament ◽  
Cerebral Ganglion ◽  
Helix Aspersa ◽  
Neurofilament Protein ◽  
Intermediate Filament Proteins ◽  
Nuclear Lamins ◽  
Untranslated Sequence ◽  
Cerebral Ganglia ◽  
Neuronal Intermediate Filament Proteins

The neuronal cytoplasmic intermediate filament (IF) protein HeNF70 of the gastropod Helix aspersa is identified by sequence analysis of the corresponding 4,600 bp cDNA isolated from a cerebral ganglion cDNA library. HeNF70 shares 60% sequence identity with the neuronal LoNF70 protein of the cephalopod Loligo pealei and only 36% identity with the Helix non-neuronal IF-A protein. All three molluscan IF proteins display the lamin-type extended coil 1b subdomain harbouring six additional heptads and all have long C-terminal sequences with substantial homology to the tail domains of nuclear lamins. The lamin-like tail domains of the two neurofilament proteins share a unique motif comprising 13 residues, which is absent from Helix IF-A and all other known non-neuronal IF proteins. HeNF70 is encoded by a 9.5 kb RNA transcript. The very long 7.2 kb 3′-untranslated sequence contains a unique 26 nucleotide repeat extending over 0.5 kb in its 5′-region. The HeNF70 mRNA is expressed at low abundancy in cerebral ganglia but not in any of the 13 non-neuronal tissues tested. In contrast, all tissues express at fairly high levels the same 4.6 and 4.2 kb mRNAs encoding the Helix non-neuronal IF-A/B proteins. Blot hybridisation studies on genomic DNA and ganglion mRNA with subprobes from the cloned HeNF70 cDNA, as well as sequence analysis of an RT-PCR generated partial cDNA encoding a putative HeNF60 protein, indicate at least two different neuronal IF genes in Helix.

The Nuclear Envelope and Human Disease

Physiology ◽  
2004 ◽  
Vol 19 (5) ◽  
pp. 309-314 ◽  
Author(s):  
Antoine Muchir ◽  
Howard J. Worman
Keyword(s):  
Membrane Proteins ◽  
Nuclear Envelope ◽  
Nuclear Membrane ◽  
Intermediate Filament ◽  
Human Disease ◽  
Aging Process ◽  
Intermediate Filament Proteins ◽  
Inner Nuclear Membrane ◽  
Nuclear Lamins ◽  
Nuclear Lamin

Mutations in nuclear lamins A and C, intermediate filament proteins of the nuclear envelope, cause diseases affecting various tissues and the aging process. We review what is known about nuclear lamin function and the different diseases caused by mutations in lamins A and C and associated inner nuclear membrane proteins.

Intermediate filament proteins: many unanswered questions, few unquestioned answers

1992 ◽  
Vol 70 (10-11) ◽  
pp. 842-848 ◽  
Author(s):  
Micheline Paulin-Levasseur
Keyword(s):  
Intermediate Filaments ◽  
Nuclear Matrix ◽  
Intermediate Filament ◽  
Expression Patterns ◽  
Supramolecular Assembly ◽  
Cellular Mechanisms ◽  
Specific Expression ◽  
Intermediate Filament Proteins ◽  
Nuclear Lamins ◽  
New Concepts

Major constituents of the cytoskeleton and the nuclear matrix, cytoplasmic intermediate filament subunits and nuclear lamins belong to a multigene family of proteins whose function is poorly understood. It has now become a general contention that important clues to the physiological roles of these proteins may reside in their developmental and tissue-specific expression patterns, as well as their cellular organization. The present review brings into focus experimental strategies that have been developed, over the past few years, to gain insights into the cellular mechanisms regulating the molecular polymorphism and supramolecular assembly of intermediate filaments. In this context new concepts are discussed that may be pivotal for the orientation of future studies on intermediate filament proteins.Key words: intermediate filaments, nuclear lamins, cytoskeleton, nuclear matrix.

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