In this task, you are given an abstract of article. Your task is to generate title for this article. Preferred titles are under thirty words.
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Question: The initiation and progression of adult-onset periodontitis has been associated with infection of the gingival sulcus by Porphyromonas gingivalis. This organism utilizes a multitude of virulence factors to evade host defenses as it establishes itself as one of the predominant pathogens in periodontal pockets. A feature common to many other oral pathogens is the production of ammonia due to its protective effect during acidic cleansing cycles in the mouth. Additionally, ammonia production by P. gingivalis has been proposed as a virulence factor due to its negative effects on neutrophil function. In this study, we describe the first purification of a peptidylarginine deiminase (PAD) from a prokaryote. PAD exhibits biochemical characteristics and properties that suggest that it may be a virulence agent. PAD deiminates the guanidino group of carboxyl-terminal arginine residues on a variety of peptides, including the vasoregulatory peptide-hormone bradykinin, to yield ammonia and a citrulline residue. The soluble protein has an apparent mass of 46 kDa, while the DNA sequence predicts a full-length protein of 61.7 kDa. PAD is optimally active at 55 degrees C, stable at low pH, and shows the greatest activity above pH 9.0. Interestingly, in the presence of stabilizing factors, PAD is resistant to limited proteolysis and retains significant activity after short-term boiling. We propose that PAD, acting in concert with arginine-specific proteinases from P. gingivalis, promotes the growth of the pathogen in the periodontal pocket, initially by enhancing its survivability and then by assisting the organism in its circumvention of host humoral defenses.

Answer: Purification, characterization, and sequence analysis of a potential virulence factor from Porphyromonas gingivalis, peptidylarginine deiminase.

Question: In response to a variety of stimuli, dendritic cells (DCs) transform from immature cells specialized for antigen capture into mature cells specialized for T cell stimulation. During maturation, the DCs acquire an enhanced capacity to form and accumulate peptide-MHC (major histocompatibility complex) class II complexes. Here we show that a key mechanism responsible for this alteration was the generalized activation of lysosomal function. In immature DCs, internalized antigens were slowly degraded and inefficiently used for peptide loading. Maturation induced activation of the vacuolar proton pump that enhanced lysosomal acidification and antigen proteolysis, facilitating efficient formation of peptide-MHC class II complexes. Lysosomal function in DCs thus appears to be specialized for the developmentally regulated processing of internalized antigens.

Answer: Activation of lysosomal function during dendritic cell maturation.

Question: HER-2/neu amplification or overexpression can make cancer cells resistant to apoptosis and promotes their growth. p53 is crucial in regulating cell growth and apoptosis, and is often mutated or deleted in many types of tumour. Moreover, many tumours with a wild-type gene for p53 do not have normal p53 function, suggesting that some oncogenic signals suppress the function of p53. In this study, we show that HER-2/neu-mediated resistance to DNA-damaging agents requires the activation of Akt, which enhances MDM2-mediated ubiquitination and degradation of p53. Akt physically associates with MDM2 and phosphorylates it at Ser166 and Ser186. Phosphorylation of MDM2 enhances its nuclear localization and its interaction with p300, and inhibits its interaction with p19ARF, thus increasing p53 degradation. Our study indicates that blocking the Akt pathway mediated by HER-2/neu would increase the cytotoxic effect of DNA-damaging drugs in tumour cells with wild-type p53.

Answer:
HER-2/neu induces p53 ubiquitination via Akt-mediated MDM2 phosphorylation