PAMPs and DAMPs: Signal 0s that Spur Autophagy and Immunity PAMPs (pathogen-associated molecular patterns) and DAMPs (damage-associated molecular patterns) are signal 0s that trigger autophagy and immunity. PAMPs are derived from microorganisms and recognized by pattern recognition receptors (PRRs) in the innate immune system and epithelial cells. DAMPs are cell-derived and initiate immunity in response to trauma, ischemia, and tissue damage, either in the absence or presence of pathogenic infection. Both PAMPs and DAMPs bind to specific receptors, such as TLRs, NLRs, RLRs, and RAGE, to promote autophagy. Autophagy is a conserved lysosomal degradation pathway that helps cells survive under stress. It is involved in both innate and adaptive immunity, with the term 'immunophagy' referring to all such processes. Autophagy degrades microbes, such as viruses, bacteria, and protozoa, that invade the cytosol, a process called xenophagy. The precise mechanisms of xenophagy are not fully understood. Autophagy involves a series of dynamic membrane-rearrangement reactions mediated by a core set of proteins, including ATG proteins. There are three primary forms of autophagy: chaperone-mediated autophagy, microautophagy, and macroautophagy. Macroautophagy is the most extensively studied and involves the formation of the phagophore, followed by the elongation and expansion of the phagophore and the closure and completion of a double-membrane autophagosome. Autophagosomes mature through vesicular fusion events and are degraded by acid hydrolases inside the autolysosome. Recycling of the resulting macromolecules is mediated through permeases. Autophagy and apoptosis are both tightly regulated biological processes that play a central role in cell survival and cell death. These two pathways are regulated by common factors such as Bcl-2 family members and various transcription factors. Autophagy is primarily a cell survival process, while apoptosis is a programmed cell death. In some cases, when apoptosis is compromised, activation of autophagy can lead to cell death. PAMPs are exogenous signal 0s that are recognized by PRRs such as TLRs, RLRs, and NLRs. They are essential functional components of microorganisms that direct the host cell to distinguish 'self' from 'non-self' and promote signals associated with innate immunity. Major PAMPs include microbial nucleic acids, lipoproteins, surface glycoproteins, and membrane components. They are recognized by TLRs and other PRRs, such as RIG-I-like receptors, AIM2-like receptors, and NOD-like receptors. DAMPs are endogenous signal 0s that can initiate and perpetuatePAMPs and DAMPs: Signal 0s that Spur Autophagy and Immunity PAMPs (pathogen-associated molecular patterns) and DAMPs (damage-associated molecular patterns) are signal 0s that trigger autophagy and immunity. PAMPs are derived from microorganisms and recognized by pattern recognition receptors (PRRs) in the innate immune system and epithelial cells. DAMPs are cell-derived and initiate immunity in response to trauma, ischemia, and tissue damage, either in the absence or presence of pathogenic infection. Both PAMPs and DAMPs bind to specific receptors, such as TLRs, NLRs, RLRs, and RAGE, to promote autophagy. Autophagy is a conserved lysosomal degradation pathway that helps cells survive under stress. It is involved in both innate and adaptive immunity, with the term 'immunophagy' referring to all such processes. Autophagy degrades microbes, such as viruses, bacteria, and protozoa, that invade the cytosol, a process called xenophagy. The precise mechanisms of xenophagy are not fully understood. Autophagy involves a series of dynamic membrane-rearrangement reactions mediated by a core set of proteins, including ATG proteins. There are three primary forms of autophagy: chaperone-mediated autophagy, microautophagy, and macroautophagy. Macroautophagy is the most extensively studied and involves the formation of the phagophore, followed by the elongation and expansion of the phagophore and the closure and completion of a double-membrane autophagosome. Autophagosomes mature through vesicular fusion events and are degraded by acid hydrolases inside the autolysosome. Recycling of the resulting macromolecules is mediated through permeases. Autophagy and apoptosis are both tightly regulated biological processes that play a central role in cell survival and cell death. These two pathways are regulated by common factors such as Bcl-2 family members and various transcription factors. Autophagy is primarily a cell survival process, while apoptosis is a programmed cell death. In some cases, when apoptosis is compromised, activation of autophagy can lead to cell death. PAMPs are exogenous signal 0s that are recognized by PRRs such as TLRs, RLRs, and NLRs. They are essential functional components of microorganisms that direct the host cell to distinguish 'self' from 'non-self' and promote signals associated with innate immunity. Major PAMPs include microbial nucleic acids, lipoproteins, surface glycoproteins, and membrane components. They are recognized by TLRs and other PRRs, such as RIG-I-like receptors, AIM2-like receptors, and NOD-like receptors. DAMPs are endogenous signal 0s that can initiate and perpetuate