Nuclear motors and nuclear structures containing A-type lamins and emerin: is there a functional link?

  title={Nuclear motors and nuclear structures containing A-type lamins and emerin: is there a functional link?},
  author={Ishita Mehta and Lauren S Elcock and Manelle Amira and Ian R. Kill and Joanna M. Bridger},
  journal={Biochemical Society transactions},
  volume={36 Pt 6},
Rapid interphase chromosome territory repositioning appears to function through the action of nuclear myosin and actin, in a nuclear motor complex. We have found that chromosome repositioning when cells leave the cell cycle is not apparent in cells that have mutant lamin A or that are lacking emerin. We discuss the possibility that there is a functional intranuclear complex comprising four proteins: nuclear actin, lamin A, emerin and nuclear myosin. If any of the components are lacking or… 

Nuclear Molecular Motors for Active, Directed Chromatin Movement in Interphase Nuclei

This chapter reviews a few studies that have started to undercover a role for actin and myosin isoforms, found in the nucleus, as nuclear motors that actively move individual gene loci, clusters of genes and whole chromosomes within the nucleoplasm.

Structure-Function Relationships of Nuclear Lamins

Nuclear lamins are type V intermediate filament proteins that form a filamentous meshwork beneath the inner nuclear membrane that protects the nucleus from mechanical stress and mediates nucleo-cytoskeletal coupling.

Telomere movement is constrained by interactions with an inner nuclear lamin structure

Results suggest that telomeres are associated to a complex con-sisting of lamin A/C, emerin and actin and that the movement of telomere is constrained by this association.

Role of A‐ and B‐type lamins in nuclear structure–function relationships

Recent research on nuclear lamins and unique roles of A‐ and B‐type lamins in modulating various nuclear processes and their impact on cell function are reviewed.

Lamina-independent lamins in the nuclear interior serve important functions.

The properties and regulation of nucleoplasmic lamins during the cell cycle, their interaction partners, and their potential involvement in cellular processes and the development of laminopathies are discussed.

Actin-related proteins in the nucleus: life beyond chromatin remodelers.

New insight into role of myosin motors for activation of RNA polymerases.

Investigating the role of nuclear myosin I in the low serum induced repositioning of chromosome 10 in interphase nuclei

Using siRNA to block the expression of the nuclear myosin I (NMI) the authors were able to identify this nuclearMyosin as necessary for the rapid repositioning of chromosome 10, and investigated the effect of the NMI knock down on the overall nuclear size and shape.

Rapid chromosome territory relocation by nuclear motor activity in response to serum removal in primary human fibroblasts

It is demonstrated that genome organization in interphase nuclei is altered considerably when cells leave the proliferative cell cycle and that repositioning of chromosomes relies on efficient functioning of an active nuclear motor complex that contains nuclear myosin 1β.



Actin-dependent intranuclear repositioning of an active gene locus in vivo

Simultaneous four-dimensional tracking of CBs and U2 genes reveals that target loci are recruited toward relatively stably positioned CBs by long-range chromosomal motion, which supports a model in which nuclear actin is required for these rapid, long- range chromosomal movements.

From transcription to transport: emerging roles for nuclear myosin I.

A recent study on intranuclear long-range chromosome movement has now demonstrated a role for NMI in the translocation of chromosome regions as well, establishing for the first time a functional role for a motor complex consisting of actin and a myosin in the nucleus.

Nuclear lamins: building blocks of nuclear architecture.

Experimental and genetic evidence suggest that nuclear lamins are involved in a number of other functions including nuclear envelope assembly, DNA synthesis, transcription, and apoptosis, and speculate about possible mechanisms through which mutations in lamins give rise to disease.

Dynamic properties of nuclear lamins: lamin B is associated with sites of DNA replication

It is demonstrated that during mid- late S-phase, nuclear foci detected with lamin B antibodies are coincident with sites of DNA replication as detected by the colocalization of sites of incorporation of bromodeoxyuridine (BrDU) or proliferating cell nuclear antigen (PCNA).

Myosin Va phosphorylated on Ser1650 is found in nuclear speckles and redistributes to nucleoli upon inhibition of transcription.

Observations indicate a novel role for myosin Va in nuclear compartmentalization and offer a new lead towards the understanding of actomyosin-based gene regulation.

Proteins that bind A-type lamins: integrating isolated clues

This work describes 16 partners in detail, summarizes their binding sites in A-type lamins, and sketches portraits of ternary complexes and functional pathways that might depend on lamins in vivo.

Colocalization of intranuclear lamin foci with RNA splicing factors.

A monoclonal antibody raised against recombinant rat lamin A that labels nuclei in a speckled pattern in all cells of unsynchronized populations of HeLa and rat F-111 fibroblast cells is characterized, consistent with a structural role for lamins in supporting nuclear compartments containing proteins involved in RNA splicing.

Lamins and lamin-associated proteins in aging and disease.

Nuclear actin: to polymerize or not to polymerize

Fluorescence recovery after photobleaching (FRAP) is used to tackle the question of whether nuclear actin exists as monomers or polymers.