malfunction
arteriviruses lacking PLP2 deubiquitinase activity elicit an enhanced host innate immune response
malfunction
mutations of residues in the enzyme-ubiquitin interface lead to reduced catalytic activity
more
enzyme structure and function, active site structure with catalytic triad residues, Cys112, His273 and Asp287 and the oxyanion hole-stabilizing residue Trp107, and catalytic mechanism, detailed overview. The fingers domain of PLpro, which contains a zinc ion that is tetrahedrally coordinated by four cysteines, is essential for catalysis because it maintains the structural integrity of the enzyme
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the enzyme comprises the viral polyprotein residues 1541-1858
physiological function
changes within the Ubl domain, residues 785 to 787 of nonstructural protein 3, negatively affect protease activity. Ubl mutant viruses V787S and V785S replicate efficiently at 37°C but generate smaller plaques than wild-type virus, and V787S is defective for replication at higher temperatures. The proteases of the mutant viruses exhibit similar specific activities at 25°C but diplay significantly reduced thermal stability at 30°C, thereby reducing the total enzymatic activity. Infection of C57BL/6 mice with V787S is highly attenuated, yet it replicates sufficiently to elicit protective immunity
physiological function
papain-like protease domain 2 (PLP2) deubiquitinates TANK-binding kinase-1 (TBK1) and reduces its kinase activity, hence inhibits interferon-beta reporter activity and prevents interferon regulatory factor 3 (IRF3) nuclear translocation. The presence of PLP2 stabilizes the hypo-phosphorylated IRF3-TBK1 complex in a dose-dependent manner in the cytoplasm
physiological function
PLP2 is responsible for the inhibition of both RIG-I and TLR3-dependent induction of interferon alpha/beta expression
physiological function
the enzyme is essential for arterivirus replication by cleaving a site within the viral replicase polyproteins and also removes ubiquitin from cellular proteins. This deubiquitinase activity is a critical factor in arteriviral innate immune evasion
physiological function
the enzyme is one of two cysteine proteases involved in the proteolytic processing of the polyproteins of Severe acute respiratory syndrome coronavirus. It also shows significant in vitro deubiquitinating and de-ISGylating activities
physiological function
the enzyme strongly inhibits RIG-Iand STING-activated interferon expression. Papain-like protease 2 acts as a viral deubiquitinase to interfere with the RIG-I- and STING-mediated signalling pathway
