Lamin promotes the repair of damaged nuclear membranes in human and mouse cells.

All living cells have a nucleus – a key biological structure that plays an important role
in information storage, retrieval, and genetic information replication.
In mammals, these nuclei have a nuclear envelope (NE) – a biological barrier
that protects the nucleus from environmental stimuli, such as mechanical stress, and related damage.
However, certain external stimuli can cause damage
to NE.
When this happens, various mechanisms begin to initiate the network element repair process
.
However, the precise mechanism of NE repair remains unclear
.

Recently, an international team of researchers led by Dr.
Takeshi Shimi, a distinguished associate professor at Tokyo Tech University, was able to determine the exact role
of key components in this important physiological process 。 Using high-power lasers to induce network element rupture, the researchers demonstrated how a "repair army" consisting of lamin C, Barrier-to-autointegration factor (BAF), and cytoplasmic cycle GMP-AMP synthase (cGAS) can synergistically promote the repair of network elements in mouse embryonic fibroblasts, important proteins with key biological functions
.
Their findings were published in
the Journal of Cell Biology.

"In mammalian nuclei, the nuclear layer is located below the NE to maintain the nuclear structure
.
The nuclear laminate is the main structural component of the nuclear laminate and participates in preventing NE rupture
caused by mechanical stress.
Our analysis using immunofluorescence and live-cell imaging showed rapid accumulation of nucleoplasmic pools of lamin C at the site of NE rupture induced by laser microirradiation in mammalian cells," explains Dr.
Shimi, detailing their findings
.

The NE repair process is sometimes hindered
due to certain mutations.
In their study, the team succeeded in identifying key lamin C mutations — structural and functional modifications
that adversely affect the repair process.
For example, they found that lamin C mutants (i.
e.
, R435C, R471C, R527H, A529V, and K542N) did not undergo rapid repair or weakening
compared to wild-type (control) lamin C without these mutations.
In addition, these two mutants are found in patients with laminopathy, which are responsible for
heart and skeletal muscle disorders, dysplasia, and Progeria-like syndrome.

Based on these findings, Dr.
Shimi concludes, "The accumulation of nuclear BAF and cGAS at the site of rupture is partly dependent on lamin A/C
.
Our results show that the nucleoplasmic layer proteins C, BAF, and cGAS collectively aggregate at the NE rupture site for rapid repair
.
”

Let's hope that the insights gained from this breakthrough will lead to a better understanding of a variety of rare genetic diseases
.

Nucleoplasmic Lamin C Rapidly Accumulates at Sites of Nuclear Envelope Rupture with BAF and cGAS