Sequestosome-1 is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respon ...
that in humans is encoded by the ''SQSTM1''
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
.
Also known as the ubiquitin-binding protein p62, it is an
autophagosome
An autophagosome is a spherical structure with double layer membranes. It is the key structure in macroautophagy, the intracellular degradation system for cytoplasmic contents (e.g., abnormal intracellular proteins, excess or damaged organelles, i ...
cargo protein that targets other proteins that bind to it for selective
autophagy
Autophagy (or autophagocytosis; from the Ancient Greek , , meaning "self-devouring" and , , meaning "hollow") is the natural, conserved degradation of the cell that removes unnecessary or dysfunctional components through a lysosome-dependent re ...
. By interacting with
GATA4
Transcription factor GATA-4 is a protein that in humans is encoded by the ''GATA4'' gene.
Function
This gene encodes a member of the GATA family of zinc finger transcription factors. Members of this family recognize the GATA motif which is pr ...
and targeting it for degradation, it can inhibit GATA-4 associated
senescence
Senescence () or biological aging is the gradual deterioration of functional characteristics in living organisms. The word ''senescence'' can refer to either cellular senescence or to senescence of the whole organism. Organismal senescence inv ...
and senescence-associated secretory phenotype.
Model organisms
Model organisms have been used in the study of SQSTM1 function. A conditional
knockout mouse
A knockout mouse, or knock-out mouse, is a genetically modified mouse (''Mus musculus'') in which researchers have inactivated, or " knocked out", an existing gene by replacing it or disrupting it with an artificial piece of DNA. They are importa ...
line, called ''Sqstm1
tm1a(KOMP)Wtsi''
was generated as part of the
International Knockout Mouse Consortium
The International Knockout Mouse Consortium (IKMC) is a scientific endeavour to produce a collection of mouse embryonic stem cell lines that together lack every gene in the genome, and then to distribute the cells to scientific researchers to cr ...
program — a high-throughput mutagenesis project to generate and distribute animal models of disease to interested scientists.
Male and female animals underwent a standardized
phenotypic screen
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological prop ...
to determine the effects of deletion.
Twenty two tests were carried out on
homozygous
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism.
Mo ...
mutant
In biology, and especially in genetics, a mutant is an organism or a new genetic character arising or resulting from an instance of mutation, which is generally an alteration of the DNA sequence of the genome or chromosome of an organism. It ...
mice and one significant abnormality was observed: females had abnormal
complete blood count
A complete blood count (CBC), also known as a full blood count (FBC), is a set of medical laboratory tests that provide information about the cells in a person's blood. The CBC indicates the counts of white blood cells, red blood cells and ...
parameters, including an increased
red blood cell
Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...
distribution width and increased mean
platelet
Platelets, also called thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are a component of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping, thereby i ...
volume.
Interactions
Sequestosome 1 has been shown to
interact
Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex traits. The organizat ...
with:
*
MAP1LC3A
Microtubule-associated proteins 1A/1B light chain 3A is a protein that in humans is encoded by the ''MAP1LC3A'' gene. Two transcript variants encoding different isoforms have been found for this gene.
Function
MAP1A and MAP1B are microtubule ...
,
*
PRKCI
Protein kinase C iota type is an enzyme that in humans is encoded by the ''PRKCI'' gene.
Function
This gene encodes a member of the protein kinase C (PKC) family of serine/threonine protein kinases. The PKC family comprises at least eight membe ...
,
*
RAD23A
UV excision repair protein RAD23 homolog A is a protein that in humans is encoded by the ''RAD23A'' gene.
Function
The protein encoded by this gene is one of two human homologs of ''Saccharomyces cerevisiae'' Rad23, a protein involved in nuc ...
,
*
RIPK1
Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) functions in a variety of cellular pathways related to both cell survival and death. In terms of cell death, RIPK1 plays a role in apoptosis and necroptosis. Some of the cell survival ...
,
*
TRAF6
TRAF6 is a TRAF human protein.
Function
The protein encoded by this gene is a member of the TNF receptor associated factor (TRAF) protein family. TRAF proteins are associated with, and mediate signal transduction from members of the TNF recept ...
*
TrkA
Tropomyosin receptor kinase A (TrkA), also known as high affinity nerve growth factor receptor, neurotrophic tyrosine kinase receptor type 1, or TRK1-transforming tyrosine kinase protein is a protein that in humans is encoded by the ''NTRK1'' gen ...
,
and
*
TrkB
Tropomyosin receptor kinase B (TrkB), also known as tyrosine receptor kinase B, or BDNF/NT-3 growth factors receptor or neurotrophic tyrosine kinase, receptor, type 2 is a protein that in humans is encoded by the ''NTRK2'' gene. TrkB is a recepto ...
.
[
* ]Nrf2
Nuclear factor erythroid 2-related factor 2 (NRF2), also known as nuclear factor erythroid-derived 2-like 2, is a transcription factor that in humans is encoded by the ''NFE2L2'' gene. NRF2 is a basic leucine zipper (bZIP) protein that may regula ...
[Feng, Lifeng et al. “Tamoxifen activates Nrf2-dependent SQSTM1 transcription to promote endometrial hyperplasia” Theranostics vol. 7,7 1890-1900. 10 Apr. 2017, doi:10.7150/thno.19135]
References
Further reading
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* Feng, Lifeng et al. “Tamoxifen activates Nrf2-dependent SQSTM1 transcription to promote endometrial hyperplasia” Theranostics vol. 7,7 1890-1900. 10 Apr. 2017, doi:10.7150/thno.19135
{{PDB Gallery, geneid=8878
Genes mutated in mice