Although the phenomenon of cell death had been known for centuries, even briefly described in the 19th century, the explosion of research and technology in the latter half of the 20th century led to greater and more nuanced discoveries that have provided insights into many physiological processes including tissue development, maintenance, metabolism, and disease states including cancer. The many accomplishments in programmed cell death research have improved our understanding and development of targeted therapeutics, and some of these milestones were recognized by Nobel Prizes for apoptosis and autophagy. As scientists continue to elucidate new cell death pathways and their interplay with other pathways, let's take a look at what we know so far and what new findings have come out.

Once upon a time when I was a fledgling science nerd in high school, I started learning about the process of apoptosis, which remains to this day the most studied form of cell death in various functions including organismal development and defense against cancer. As an immunologist-in-training, I also learned about the classical complement pathway that the immune system uses to destroy infected cells, and also necrotic cell death or necroptosis (which is full of really gross pictures if you dare to Google it). Of course, I learned about autophagy in graduate school and really appreciate its utility in normal physiology and disease, while very recently I read about ferroptosis as yet another programmed cell death (PCD) pathway. Right around when the Nobel Prize was awarded to recognize the elucidation of PCD, pyroptosis came about as a novel PCD pathway that is continuing to gain steam in its clinical relevance. It seems logical for cells and organisms to have redundant systems in place to clear away damaged and malignant cells before a health crisis can emerge if the cell evades the primary route of apoptosis.

Every now and then when I get hungry, I joke that my stomach is about to digest itself. For the longest time, human science was unaware that our cells could literally eat itself (or more precisely, parts of itself) as well! First described in the 1960s by Christian de Duve (who won the Nobel Prize for discovering the lysosome), the term autophagy derives from Greek words combined to mean “self-eating” and describes a process by which the cell degrades large components and organelles in a distinct mechanism. ^1-3 The phenomenon was not studied extensively until the 1990s, when Yoshinori Ohsumi performed a series of groundbreaking experiments to determine the underlying mechanisms of autophagy, an achievement for which he was awarded the 2016 Nobel Prize in Physiology or Medicine. Ohsumi’s work has led to an explosion of research that has precipitated a greater understanding of the role played by cellular digestion, degradation, and recycling pathways in human health and disease.

Autophagy can be understood as ‘self-eating’. In simple terms, it is a vitally important cleansing mechanism carried out by the cells in our body. It brings about the degradation of the cytoplasmic contents within membrane bound vesicles called lysosomes.

Autophagy is a catabolic process in which autophagic lysosomes, known as autophagosomes, degrade most cytoplasmic contents, including entire organelles like damaged mitochondria in protection of the host cell and organism. Autophagy is usually activated in the absence of nutrients and is associated with many physiological and pathological processes, including growth, differentiation, neurodegenerative diseases, infections and tumors. Light chain 3 (LC3) is a widely recognized autophagy marker. There are three isoforms of the LC3 protein (LC3A, LC3B, and LC3C) in mammals. They undergo post-translational modifications during autophagy. The LC3 protein is first cleaved by Atg4 at its carboxy terminus immediately after synthesis to produce LC3-I, which is localized in the cytoplasm. During autophagy, LC3-I is modified and processed by a ubiquitin-like system including Atg7 and Atg3 to produce LC3-II with a molecular weight of 14 kD and localized to autophagosomes. The magnitude of the LC3-II/I ratio can be used to assess the level of autophagy.

ABclonal Technology is pleased to offer numerous antibody products to study targets within the autophagy pathway, be it the normal functions within the pathway, the autophagic cell death pathway, or disruptions to autophagy that may drive disease progression. Many of our products have been peer reviewed by satisfied customers, including those who have used them to generate quality data for scientific publications. Please see some examples of our products below, and happy experimenting!