Antibody database

Lysosomes are membrane-bound organelles responsible for the degradation of various biological macromolecules. Vesicles containing hydrolytic enzymes bud from the Golgi and fuse with endosomes to form the mature lysosome capable of breaking down various types of cargo. Their general function in recycling biological molecules places lysosomes at center of various processes including autophagy, endyocytosis, and phagocytosis.

The transforming growth factor-β (TGF-beta) family consists of a wide variety of signaling proteins with roles in development. TGF-beta signaling controls growth, differentiation, and immune responses and is often misregulated in cancer. TGF-beta 1 is the most widely expressed and abundant isoform of the TGF-beta family. TGF-beta proteins signal through two classes of receptors: type I (TβRI) and type II (TβRI). These receptor proteins are serine threonine kinases found at the cell surface.

PTEN-induced putative kinase 1 (PINK1) is a serine/threonine kinase with important functions in mitochondrial quality control. Together with the Parkin protein, PINK1 is able to regulate the selective degradation of damaged mitochondria through autophagy. Normally PINK1 is imported into the mitochondria where it is targeted for proteolytic cleavage. This cleavage event results in unstable products and is the reason PINK1 is difficult to detect in healthy mitochondria.

Noxa is a BH3-only protein involved in regulating cell death decisions. Noxa is a primary p53-response gene and is upregulated in response to p53 overexpression or DNA damage. Noxa can also be induced by alternative mechanisms including through a hypoxia-response element found in its promoter. Noxa localizes to mitochondria where it binds to Mcl1, an anti-apoptotic Bcl2 family member.

During cellular stress the protein folding capacity of the ER is diminished. In order to maintain homeostasis and ensure proper protein folding cells activate the unfolded protein response (UPR), a signaling network consisting of sensors and effectors to enhance the chaperone activity of the cell, increase degradation of accumulated proteins, and/or trigger apoptosis.  Inositol-requiring enzyme 1 (IRE1), an ER-transmembrane protein, is an essential component of the UPR pathway important for sensing and responding to ER stress.

Autophagy is important for the removal of damaged organelles or proteins as well as for the regulation of cellular homeostasis in response to stress. Proteins or organelles that are targeted for degradation are engulfed in a double-membrane structure called the autophagosome that eventually fuses with the lysosome to mediate cargo degradation. Atg5 plays an important regulatory role in the early steps of this process.

During times of cellular stress overloading of the protein folding machinery leads to the accumulation of incorrectly folded proteins. This triggers the unfolded protein response (UPR) in order to try to reestablish homeostasis or, if this fails, to induce apoptosis. The UPR pathway is mediated by a group of ER-associated transmembrane receptors including activating transcription factor 6 (ATF6). The presence of misfolded proteins is monitored by BiP, an Hsp70 family member.

Scavenger receptors play important roles in homeostasis and innate immunity by binding to endogenous and foreign molecules. Scavenger receptors on the plasma membrane of macrophages bind to ligand and allow their internalization and can also mediate pro- or anti-inflammatory signaling. The plasma membrane glycoprotein CD163 is a member of the scavenger receptor cysteine-rich (SRCR) protein family. CD163 contains nine SRCR domains and is expressed in macrophages and monocytes where it plays a role in innate immunity and regulation of inflammation in response to ligand binding.

Autophagy is an essential cellular process that maintains homeostasis through the degradation and recycling of cytoplasmic organelles and macromolecules. Substrates targeted for autophagy are engulfed in a double-membrane structure called the autophagosome which is then targeted to the lysosome for degradation. The initiation of autophagy requires two separate ubiquitin-like protein (UBL) systems that regulate autophagosome assembly. In these systems Atg7 acts as an E1-like enzyme for the UBLs Atg12 and Atg8.

During autophagy ubiquitinated cargo or substrates are engulfed in a double-membrane autophagosome and transported to the lysosome for degradation. This process is important for maintaining cellular homeostasis and for degrading damaged organelles or misfolded protein aggregates. p62, also known as sequestosome 1 (SQSTM1), is an autophagy receptor that recognizes and recruits cargo to the autophagosome through its interaction with Atg8.