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Information about Lamin

Lamins are fibrous proteins having structural function in the cell nucleus.

In metazoan cells there are A and B type lamins which differ in their length and pI. Human cells have three differentially regulated genes.
  • B-type lamins are present in every cell. B type lamins, B1 and B2, are expressed from the LMNB1 and LMNB2 genes on 5q23 and 19q13, respectively.
  • A-type lamins are only expressed following gastrulation. Lamin A and C are the most common A-type lamins and are splice variants of the LMNA gene found at 1q21.
These proteins localize to two regions of the nuclear compartment, the nuclear lamina -- a proteinaceous structure layer subjacent to the inner surface of the nuclear envelope and throughout the nucleoplasm in the nucleoplasmic "veil".

Comparison of the lamins to vertebrate cytoskeletal IFs shows that lamins have an extra 42 residues (six heptads) within coil 1b. The c-terminal tail domain contains a nuclear localization signal (NLS), an Ig-fold like domain, and in most cases a carboxy-terminal CaaX box that is isoprenylated and carboxymethylated (lamin C does not have a CAAX box). Lamin A is further processed to remove the last 15 amino acids and its farnesylated cysteine.

During mitosis, lamins are phosphorylated by MPF which drives the disassembly of the lamina and the nuclear envleope.

See also

External links

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Proteins of the cytoskeleton
MicrofilamentsActins - Actin-binding proteins - Actinin - Arp2/3 complex - Cofilin - Destrin - Gelsolin - Myosins - Profilin - Tropomodulin - Troponin (T, C, I) - Tropomyosin - Wiskott-Aldrich syndrome protein
Intermediate filamentstype 1 and 2 (Cytokeratin, type I, type II) - type 3 (Desmin, GFAP, Peripherin, Vimentin) - type 4 (Internexin, Nestin, Neurofilament, Synemin, Syncoilin) - type 5 (Lamin A, B)
MicrotubulesDyneins - Kinesins - MAPs (Tau protein, Dynamin) - Tubulins - Stathmin
CateninsAlpha catenin - Beta catenin - Plakoglobin (gamma catenin) - Delta catenin
NonhumanMajor sperm proteins - Prokaryotic cytoskeleton (Crescentin, FtsZ, MreB)
OtherAPC - Dystrophin (Dystroglycan) - plakin (Desmoplakin, Plectin) - Spectrin - Talin - Utrophin - Vinculin
Fibrous proteins, also called scleroproteins, are long filamentous protein molecules that form one of the two main classes of tertiary structure protein (the other being globular proteins). Fibrous proteins are only found in animals.
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nucleus (3) ribosome (4) vesicle (5) rough endoplasmic reticulum (ER) (6) Golgi apparatus (7) Cytoskeleton (8) smooth ER (9) mitochondria (10) vacuole (11) cytoplasm (12) lysosome (13) centrioles]]

In cell biology, the nucleus (pl.
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The isoelectric point (pI) is the pH at which a particular molecule or surface carries no net electrical charge. Amphoteric molecules called zwitterions contain both positive and negative charges depending on the functional groups present in the molecule.
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For a non-technical introduction to the topic, see .
A gene is a locatable region of genomic sequence, corresponding to a unit of inheritance, which is associated with regulatory regions, transcribed regions and/or other functional sequence regions.
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Gastrulation is a phase early in the development of animal embryos, during which the morphology of the embryo is dramatically restructured by cell migration. Gastrulation varies in different phyla.
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nucleus (3) ribosome (4) vesicle (5) rough endoplasmic reticulum (ER) (6) Golgi apparatus (7) Cytoskeleton (8) smooth ER (9) mitochondria (10) vacuole (11) cytoplasm (12) lysosome (13) centrioles]]

In cell biology, the nucleus (pl.
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The nuclear lamina is a dense, ~ 30 to 100 nanometers thick, fibrillar network composed of intermediate filaments made of lamin that lines the inner surface of the nuclear envelope in animal cells.
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The nuclear envelope (also known as the perinuclear envelope, nuclear membrane, nucleolemma or karyotheca) is the double membrane of the nucleus that encloses genetic material in eukaryotic cells.
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A nuclear localizing sequence (NLS) is an amino acid sequence which acts like a 'tag' on the exposed surface of a protein. This sequence is used to target the protein to the cell nucleus through the Nuclear Pore Complex and to direct a newly synthesized protein into the
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Intermediate filaments (IFs) are cytoskeletal structures formed by members of a family of related proteins. Intermediate filaments have a diameter between that of actin (microfilaments) and microtubules.
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The nuclear lamina is a dense, ~ 30 to 100 nanometers thick, fibrillar network composed of intermediate filaments made of lamin that lines the inner surface of the nuclear envelope in animal cells.
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Laminopathies are a group of rare genetic disorders caused by mutations in genes encoding proteins of the nuclear lamina. They are included in the more generic term nuclear envelopathies that was coined in 2000 for diseases associated with defects of the nuclear envelope.
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Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed
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Proteins are large organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid residues.
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cytoskeleton is a cellular "scaffolding" or "skeleton" contained, as all other organelles, within the cytoplasm. It is contained in all eukaryotic cells and recent research has shown it can be present in prokaryotic cells too.
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Microfilaments are the thinnest filaments of the cytoskeleton found in the cytoplasm of all eukaryotic cells. These linear polymers of actin subunits are flexible and relatively strong, resisting buckling by multi-piconewton compressive forces and filament fracture by nanonewton
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Actin is a globular structural, 42-47 kDa protein found in many eukaryotic cells, with concentrations of over 100 μM. It is also one of the most highly conserved proteins, differing by no more than 5% in species as diverse as algae and humans.
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This is a list of actin-binding proteins in alphabetical order.
List: 0–9 A B C D E F G H I J K L M N O P Q R S T U V W x Y Z
References  External links

0–9

  • 25kDa
  • 25kDa ABP from aorta p185neu

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Actinin is a microfilament protein. α-Actinin is necessary for the attachment of actin filaments to the z-line membrane, in muscle cells. The functional protein is an anti-parallel dimer, which cross-links the thin filaments in adjacent sarcomeres, and therefore coordinated
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Arp2/3 complex is a seven-subunit protein that plays a major role in the regulation of the actin cytoskeleton. It is a necessary component of the actin cytoskeleton and is therefore ubiquitous in actin cytoskeleton-containing eukaryotic cells.[1].
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Identifiers
Symbol CFL2

Entrez 1073
HUGO 1875
OMIM 601443

RefSeq NM_021914
UniProt Q9Y281
Other data

Locus Chr. 14 ADF/cofilin is a family of actin-binding proteins which disassembles actin filaments.
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Destrin is a protein in microfilaments.

External links

  • MeSH Destrin


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Gelsolin is an actin-binding protein that is a key regulator of actin filament assembly and disassembly. Gelsolin is one of the most potent members of the actin-severing gelsolin/villin superfamily, as it severs with nearly 100% efficiency.
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Myosins are a large family of motor proteins found in eukaryotic tissues. They are responsible for actin-based motility.

Structure and Function

Domains

Most myosin molecules are composed of both a head and a tail domain.
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Profilin is an actin-binding protein involved in cytoskeleton dynamics. It is found in most eukaryotic cells and in mammalian cells two kinds of profilin have been discovered; Profilin I and II.
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Tropomodulin is a protein which binds and caps actin.

Genes

  • TMOD1
  • TMOD2
  • TMOD3
  • TMOD4

External links

  • MeSH Tropomodulin

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Troponin is a complex of three proteins that is integral to muscle contraction in skeletal and cardiac muscle, but not smooth muscle. Troponin is attached to the protein tropomyosin and lies within the groove between actin filaments in muscle tissue.
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Troponin T is a part of the troponin complex. It binds to tropomyosin, interlocking them to form a troponin-tropomyosin complex.

The tissue specific subtypes are:
  • Slow skeletal troponin T1, TNNT1 (19q13.

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Troponin C is a part of the troponin complex. It binds to calcium ions to produce movement.

The tissue specific subtypes are:
  • Slow troponin C, TNNC1 (3p21.3-p14.3, Mendelian Inheritance in Man (OMIM) 191040 )
  • Fast troponin C, TNNC2 (20q12-q13.

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