Antibody News

Cross-talk between proteasome degradation and lysosomal degradation

Tuesday, February 20, 2018 - 11:39
Autophagy Pathway

By Christina Towers, PhD.

Misfolded and damaged proteins are degraded by two canonical mechanisms in the cell including the ubiquitin-mediated proteasome system (UPS) and autophagy.  Proteins can be targeted for degradation by their N-terminal amino acid which can be modified to become an N-degron.  N-degrons allow for selective degradation first through the UPS, however, if the proteasome is not highly functional, these proteins may be degraded via autophagy, a lysosomal mediated form of proteolysis 1. While many studies have shown that...

Application Focus: New Methods for iPSC Differentiation, Inducing a Mammary Fate

Monday, February 12, 2018 - 15:51
Lactalbumin Antibody Immunohistochemistry Paraffin NBP1-87715

Discovery of the Key to Pluripotency

Induced pluripotent stem cells (iPSCs) may be generated from a wide range of fully differentiated cells, and under optimal conditions may be prompted to differentiate into virtually any fate. Induced stem-like cells not only provide an alternative to embryonic stem cells, but more importantly represent powerful tools for drug development and disease modeling.1

Methods for the induction of pluripotency were developed in 2006, when genes critical for cellular reprograming were identified by Yamanaka and Takahashi, including OCT4, SOX2,...

Stemness for Surviving Hypoxia: TGF-beta/Smad Signaling in Multiple Myeloma

Tuesday, February 6, 2018 - 13:06
TGF-B Pathway

By Jamshed Arslan Pharm.D.

Multiple myeloma (MM) is a cancer of antibody-producing plasma cells. The bone marrow (BM) of MM patients is hypoxic, and MM cells overexpress many cancerous genes that are regulated by hypoxia-inducible factors (HIFs). Cancer stem cells (CSCs) in the hypoxic BM regions are blamed for the incurability of MM, because CSCs are often resistant to drugs currently used against BM cancers (including proteasome inhibitors and immunomodulatory agents). Dr. Eishi Ashihara at the Kyoto Pharmaceutical University, Japan, and colleagues, set out to characterize the biology of MM stem cells. They found that TGF-beta...

CaMKII stimulates autophagic degradation of 'ID', a new frontier against cancer

Tuesday, January 30, 2018 - 13:32
A-Phagy f2 - molecular machinery

By Yoskaly Lazo-Fernandez, PhD

The field of Cancer Stem Cell (CSC) research has been gaining traction in recent years1. CSCs are a minority group of cells (usually about 1 in 10000) within solid tumors of hematological cancers, which possess similar characteristics to normal stem cells. It is believed that these cells, which are identified by markers usually only found on tissue stem cells, are the only cancerous cells that can induce tumor development and propagation or metastasis2. Consequently, gaining a better understanding of the molecular machinery...

Characterization of Stress-Related Deamidation in Therapeutic Proteins

Tuesday, January 23, 2018 - 15:02

Therapeutic proteins such as monoclonal antibodies (mAbs) can be subject to physical or chemical stress during the manufacturing process and supply chain. A common chemical degradation is the deamidation of the amino acid asparagine to aspartic acid or iso-aspartic acid. Modification of glutamine to glutamic acid is also possible, although this occurs at a slower rate. When deamidation occurs in the antigen binding region of the mAb, it can result in a loss of potency. This sequence liability may be defined as a critical quality attribute and represents a risk to the development of novel biologics and biosimilars alike.  As such, it is important to have reliable protein characterization methods with sufficient sensitivity and selectivity to identify and quantify levels of deamidation.

Physicochemical analysis

The transformation of an amide side-chain, via a succinimide intermediate, to a carboxylic acid results in a change in the net charge of the...

Marked for Deletion: Parkin Ubiquitinylates HIF-1α to Stop Cancer

Tuesday, January 23, 2018 - 08:17
Parkin Ubiquitinylates HIF-1 alpha

By Jamshed Arslan Pharm.D.

Parkin got its name from Parkinson’s disease (PD). Being an E3 ubiquitin ligase enables Parkin to ubiquitinate and degrade proteins involved in PD (such as CDCrel-1, α-synuclein, and synphilin-1). Now we know that mutations in the Parkin gene (PARK2) can not only lead to a hereditary form of PD, but may also make people prone to various malignancies including breast cancer. Hypoxia-inducible factor-1α (HIF-1α), which adapts cells to hypoxic conditions in...

Brain size matters: MTOR regulates autophagy and number of cortical interneurons

Tuesday, January 16, 2018 - 09:08
MTOR and autophagy

By Jamshed Arslan Pharm.D.

Interneurons transmit impulses between other neurons, in part, to facilitate the birth of neurons. Cortical interneurons themselves arise from the progenitors in the ventral telencephalon, a brain region that generates basal ganglia. The role of mechanistic target of rapamycin (MTOR) signaling in this process is poorly understood, even though MTOR is known to determine brain size. By deleting Mtor in mouse interneuron progenitors and their progeny, Dr. Woo-Yang Kim’s team at the University of Nebraska Medical Center, USA, found two homeostatic activities of MTOR in the developing brain: regulation of autophagy and...

Chaperone Mediated Autophagy (CMA) does it all!

Tuesday, January 9, 2018 - 11:01
HSPA8/HSC71/HSC70 Antibody

By Christina Towers, PhD.

The degradation of cellular proteins is a critical step of both regulation and quality control and results in the turn over and recycling of critical amino acids. The two main mechanisms of protein degradation converge on either the proteasome or the lysosome, the latter of which can be further subdivided into macroautophagy, microautophagy, and chaperone mediated autophagy.

 Macroautophagy is the...

The Many Connections Between Autophagy and Kidney Disease

Tuesday, January 2, 2018 - 13:28
Autophagy Pathway

By Yoskaly Lazo-Fernandez, PhD

The first description of what is called today an autophagosome was given in a paper published in 1957. Its author employed electron microscopy to observe the neonatal features of mouse kidneys1. Autophagosomes where then described as large round bodies found in the cytoplasm, primarily of proximal tubule epithelial cells, and consisting of an amorphous material containing concentrically lamellar structures and mitochondria. It was not by chance that these structures were found in kidney tubules, because autophagy plays an essential role in kidney function both in health and disease2,3. This blog will briefly introduce the main...

From Then ‘till Now: The History of Autophagy and Cancer Research

Tuesday, December 26, 2017 - 09:44
Autophagy Handbook

By Christina Towers, PhD.

The fundamental process that cells use to degrade damaged cytoplasmic material and recycle nutrients is called autophagy.  This term was first coined by the Belgium biochemist Christian de Duve stemming from the Greek translations of “auto” meaning “self” and “phagy” meaning “eat”, thus: “autophagy” translates to “eating one’s self”.  de Duve’s seminal work identified the previously unknown organelle, the lysosome and transpired in a Nobel Prize in Medicine in 19741.

Almost 4 decades after de Duve...

Friends become Foes: Molecular Chaperons, Hsp70 and Hsp90, Cause Muscle Wasting in Cancers

Tuesday, December 19, 2017 - 09:03
Exosome research

By Jamshed Arslan Pharm.D.

Muscle atrophy is a common feature of many tumors. Cancer-induced muscle wasting, or cancer cachexia, results from pro-inflammatory cytokines (TNFα and IL-6) and/or agonists of type IIB activin receptors (ActRIIB), but the key humoral factors have remained elusive. Animal studies have implicated systemic inflammation-induced activation of p38β MAPK-C/EBPβ signaling, but the etiology of cancer cachexia was unclear until recently. A team led by researchers at the University of...

Forecasting and Targeting a Rare Cancer with Hypoxia-Inducible Factor

Tuesday, December 12, 2017 - 08:57
H1alpha67

By Jamshed Arslan Pharm.D.

Cancers of nerve, adipose, and other soft tissues are called soft tissue sarcomas (STS). Malignant peripheral nerve sheath tumor (MPNST) is an example of a rare and hard-to-treat STS; even after the surgical removal (which is the only viable option), the tumor often relapses causing poor patient survival. The search for novel treatment targets led a team of researchers in Japan [1] to a transcription factor called hypoxia-inducible factor (HIF). Normally, HIF-1α adapts cells to hypoxic conditions by localizing to the nucleus where it regulates cell growth with the help of transcriptional co-activators...

CD95 Mediates Neurovascular Development

Tuesday, December 5, 2017 - 11:36
CD95 Mediates Neurovascular Development

By Yoskaly Lazo-Fernandez, PhD

The cell surface receptor CD95 (also known as Fas or APO-1) is the best-characterized member of the tumor necrosis factor (TNF) receptor superfamily1. Many receptors in this family, including CD95 are called Death Receptors because of their ability to induce apoptosis2. In cells expressing CD95, apoptosis is triggered by the binding of this receptor’s specific ligand, CD95L. This mechanism, which was originally discovered in the early nineties, allows CD95L...

Breast Cancer Survives by Releasing Self-Serving Glutamate

Tuesday, November 28, 2017 - 15:24
H1alpha67

By Jamshed Arslan Pharm.D.

Triple-negative breast cancer (TNBC) is difficult to treat because it does not express the receptors (estrogen, progesterone, and HER2) against which effective therapies are available. TNBC defeats the body’s regulation on unchecked growth, but its winning strategy remained unclear until recently. A research team, led by Dr. William Kaelin at the Dana-Farber Cancer Institute in Boston, recently discovered that TNBC cells release glutamate to disable a cancer-stunting enzyme, EglN1. This enzyme targets the...

How to switch from apoptotic to necroptotic cell death? Answer: Autophagy!

Tuesday, November 21, 2017 - 08:49

By Christina Towers, PhD.

It has long been known that programmed cell death can take place in many forms.  The most well characterized form, apoptosis, occurs when either extrinsic or intrinsic stimuli stimulate signaling cascades that result in a series of caspase cleavage events resulting in cleavage and activation of the effector caspase-3.  The end result is cell shrinkage, condensation and cleavage of chromosomal DNA, and plasma membrane blebbing that leaves the cell membrane intact1.  Apoptotic cells are engulfed by antigen presenting cells and induce anti-inflammatory and tolerogenic immune responses2.  Alternatively, necroptosis, a programmed form of necrosis, is less characterized.  However, it is now known that this process is also tightly regulated and mediated by a complex...

Autophagy’s Paradoxical Role in ALS

Tuesday, November 14, 2017 - 10:21

By Yoskaly Lazo-Fernandez, PhD

Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, is a progressive neurological disease that affects the motor neuron system and thus voluntary control of muscle movement. This disease belongs to a broader group of disorders known as motor neuron diseases, characterized by progressive degeneration and death of motor neurons. There are two types of motor neurons, including upper- and lower-motor neurons, based on the position of their somas within the CNS. Upper motor neuron somas are located in the motor cortex and their axons descend to the spinal cord where they activate the lower motor neurons. Lower motor neurons have somas within the spinal cord and extend their axons peripherally to innervate skeletal muscles. In ALS patients...

Autophagy as a Therapeutic Target: The Double-edged Sword

Tuesday, November 7, 2017 - 09:46

By Christina Towers, PhD

Autophagy is an important cellular process that facilitates the degradation of damaged cytoplasmic material and toxic protein aggregates. Its role in neuronal function is apparent by the neurodegenerative phenotypes observed in autophagy deficient genetic mouse models. Mice with neuron-specific knock out of the core autophagy protein, ATG7, are viable but most go on to develop behavioral defects and eventually massive neuronal loss in the cerebral corticies1.

But perhaps the most causative links between autophagy and neurological functioning have been observed in animal models of progressive neurodegenerative diseases including Alzheimer’s, Parkinson’s, and Huntington’s disease. Each of these devastating diseases is characterized by a build-up of toxic protein aggregates: β-...

Polyglutamine Tracts as Autophagy Regulators

Tuesday, October 31, 2017 - 09:20

By Yoskaly Lazo-Fernandez, PhD

Polyglutamine tracts (polyQ tracts) are long chains of glutamine amino acidspresent in the sequence of many proteins. The length of polyQ tracts within proteins varies significantly as normal alleles of specific genes usually contain different number of the cytosine-adenine-guanine (CAG) nucleotide repeats1.

It has long been known that polyQ tracts play a role in the etiology of several inheritable neurodegenerative disorders, including spinocerebellar ataxia, and Huntington's disease2. These 'polyglutamine diseases' result from the excessive elongation of a polyQ tract in a particular gene which causes the resultant protein to become toxic. The toxicity of mutated polyQ tracts has been extensively studied and several explanatory hypotheses have been proposed: aggregation of polyQ tract proteins, transcriptional dysregulation, mitochondrial dysfunction, and impairment of both the ubiquitin-...

Autophagy and Apoptosis: who regulates whom?

Monday, October 23, 2017 - 13:13

By Christina Towers, PhD

Apoptosis, or programmed cell death, is the result of an intricate cascade of signaling events that is initiated by extrinsic (death receptor mediated) and intrinsic (mitochondrial mediated) stimuli.  Extrinsic apoptosis is initiated by ligand binding to death receptors followed by signaling cascades that activate caspase-8, also known as the initiator caspase.  The effector caspase-3 can be activated by caspase-8, but is usually activated downstream of the intrinsic pathway, and often the extrinsic pathway will converge on the intrinsic for more efficient programmed cell death. Intrinsic signaling takes place on the mitochondrial membrane, where BH-3 only proteins activate mitochondrial outer membrane permeabilization (MOMP) and the release of mitochondrial proteins like cytochrome c.  Subsequently, the apoptosome is formed by a...

Beyond Genes: Treating Memory Loss with Minimum Adverse Effects

Tuesday, October 17, 2017 - 12:43

By Jamshed Arslan Pharm.D.

Alzheimer’s disease (AD) robs people of their memory and identity. One characteristic feature of AD is the increased expression of the enzyme, histone deacetylase-2 (HDAC-2). This protein stops the expression of some memory-forming genes by condensing them. So, memory can be enhanced by inhibiting HDAC-2. However, this approach is dangerous since HDAC-1, a close family member of HDAC-2, would also become inhibited, resulting in neuronal death and other toxic effects. New research,[1] led by Li-Huei Tsai at the Massachusetts Institute of Technology, Cambridge, suggests a novel way to specifically repress HDAC-2 by targeting the domain of HDAC-2 that makes a complex with the transcription factor, Sp3.

...

There's an autophagy for that!

Tuesday, October 10, 2017 - 13:09

By Christina Towers, PhD

A critical mechanism that cells use to generate nutrients and fuel metabolism is through a process called autophagy.  This process is complex and involves over 20 different proteins, most of which are highly conserved across species.  It involves the formation of a double membrane structure known as an autophagasome that fuses with the lysosome to facilitate the degradation of cytoplasmic material.  While bulk autophagy is thought to be largely non-specific, clearing damaged proteins from the cytoplasm, recent studies have begun to highlight more selective forms of autophagy.  Selective autophagy, also coined organellophagy, facilitates the degradation of specific organelles that are damaged or targeted for recycling.  Thus far, researchers have begun to investigate the selective degradation of mitochondria, peroxisomes, endoplasmic reticulum (ER), nuclei, and chloroplasts in plants, all mediated through variant forms of...

HIF-1 alpha and HIF-2 alpha in Muscle Development

Tuesday, October 3, 2017 - 11:42

By Bethany Veo, PhD

Our muscle cells develop from myogenic stem cells or satellite cells which have the capacity to grow, self-renew, differentiate, and regenerate under the influence of changing oxygen levels sensed from the microenvironment. Hypoxia-inducible factors HIF-1 alpha and HIF-2 alpha are transcription factors that respond to low oxygen levels, activating the expression of target genes. The current understanding of the role that HIF-1 alpha and HIF-2 alpha play in muscle development is contradictory. Case in point, upregulation and downregulation of HIF-1 alpha inhibit myoblast differentiation depending on the oxygen level in vitro.

Transgenic models including mice lacking HIF-2 alpha exhibit early embryonic arrest and HIF-1 alpha knockouts are lethal. Whereas HIF-1 alpha knockouts generated with a different Cre-...

Necroptosis in Health and Disease

Tuesday, September 26, 2017 - 09:22

By Bethany Veo, PhD

Necroptosis occurs when cells fail to undergo apoptosis following inflammatory, oxidative or ischemic stressors. Necroptotic cell death removes damaged cells and cells no longer critical for development, independently of caspase activation.  Whereas apoptotic cells display condensed nuclei and fragmentation, the telltale signs of necroptosis are plasma membrane permeabilization and mitochondria swelling.  As a regulated cell death mechanism, the process of necroptosis is necessary for maintaining cellular homeostasis during development and as a response to cellular stress conditions.  

Initiation of necroptosis results from blocking pro-survival cues from inhibitors of apoptosis.  Signaling through TNFa (tumor necrosis factor), FASL (FAS ligand) and TRAIL (Tumor...

PINK1 as a Mitochondrial Health Sensor and Neuroprotector

Tuesday, September 19, 2017 - 09:40

By Bethany Veo, PhD

Mitochondria are most commonly known as the power houses of the cell, facilitating major functions such as oxidative phosphorylation and cellular respiration.  Maintenance of mitochondria is essential to a cells' physiological homeostasis and requires oversight by several factors.  PINK1 is a serine/threonine protein kinase which localizes to the mitochondrion and regulates its function and turnover by sensing when mitochondria are damaged.1  The foremost mechanisms of mitochondrial health upkeep include fusion and fission, mitophagy, and mitochondrial transport. PINK1 is critical for mitochondrial health by facilitating all of these pathways, which serve as a quality control system to remove dysfunctional or damaged mitochondrion from the cell.  In fact, mutations in PINK1 are linked with Parkinson's disease, where dysfunction in mitophagy, mitochondrial clearance and...

Autophagy: Pro or Anti-tumorigenic? And the role of epigenetics in this debate

Monday, September 11, 2017 - 11:26

By Christina Towers, PhD

Autophagy is an evolutionarily conserved process that cells use to break down damaged cytoplasmic constituents in order to fuel cellular metabolism, particularly in instances of stress. This process has been heavily implicated in a variety of diseases, most noteworthy are neurological disorders and cancer. The role of autophagy in cancer is context dependent and somewhat controversial1. It was originally suggested by Dr. Beth Levine's group that autophagy is tumor suppressive, a claim supported by loss of the core autophagy gene, BECN1, in many tumor types including breast, prostrate, and ovarian2. However, critics of this notion point out the important observation that BECN1 is adjacent to the heavily deleted tumor suppressor gene, BRCA1,...

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