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These authors contributed equally to this work. SUMMARYRecognition of microbe-associated molecular patterns (MAMPs) initiates pattern-triggered immunity in host plants. Pattern recognition receptors (PRRs) and receptor-like cytoplasmic kinases (RLCKs) are the major components required for sensing and transduction of these molecular patterns. However, the regulation of RLCKs by PRRs and their specificity remain obscure. In this study we show that PBL27, an Arabidopsis ortholog of OsRLCK185, is an immediate downstream component of the chitin receptor CERK1 and contributes to the regulation of chitin-induced immunity in Arabidopsis. Knockout of PBL27 resulted in the suppression of several chitin-induced defense responses, including the activation of MPK3/6 and callose deposition as well as in disease resistance against fungal and bacterial infections. On the other hand, the contribution of PBL27 to flg22 signaling appears to be very limited, suggesting that PBL27 selectively regulates defense signaling downstream of specific PRR complexes. In vitro phosphorylation experiments showed that CERK1 preferentially phosphorylated PBL27 in comparison to BIK1, whereas phosphorylation of PBL27 by BAK1 was very low compared with that of BIK1. Thus, the substrate specificity of the signaling receptor-like kinases, CERK1 and BAK1, may determine the preference of downstream RLCKs.

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Much evidence has accumulated that the epidermal growth factor receptor (EGFR) and its family members are strongly implicated in the development and progression of lung cancers. Somatic mutations of the EGFR gene were found in about 25-40% of Japanese lung cancer patients. More recently, erbB2 mutations are found in about 4% of European-derived lung cancer patients. We have investigated EGFR and erbB2 mutation status in 95 surgically treated nonsmall cell lung cancer (NSCLC) cases from Nagoya City University Hospital. Seventy-five adenocarcinoma cases were included. The presence or absence of EGFR and ernB2 mutations of kinase domains were analyzed by reverse transcription polymerase chain reaction (RT-PCR) amplifications and direct sequences. We have also investigated erbB2 mutation status in 27 surgically treated NSCLC cases followed by treatment with gefitinib from Kinki-chuo Chest Medical Center. EGFR mutations (CTGfiCGG; L858R) were found from 14 of 95 lung cancer patients. We also detected the deletion 1a-type mutations from 9 patients and deletion 4-type mutations from 6 patients in exon 19. In exon 20, 4 mutations including 2 novel mutations were found. Total EGFR mutations were present in 35 patients (36.8%). These mutation statuses were significantly correlated with gender (women 73.3% vs. men 20%, p < 0.0001), smoking status (never smoker 69.4% vs. smoker 16.9%, p < 0.0001), pathologic subtypes (adenocarcinoma 45.1% vs. nonadenocarcinoma 12.5%, p 5 0.0089) and differentiation status of the lung cancers (well 51% vs. moderately or poorly 18.4%, p 5 0.0021). On the other hand, erbB2 mutation was only found from 1 of 95 patients, at exon 20. This patient was female and a never smoker with adenocarcinoma. This 12 nucleotide insertion mutation (2324-2325 ins ATACGTGATGGC) was located in the exon 20 at kinase domain (775-776 ins YVMA). There was no erbB2 mutation in 27 gefitinib-treated NSCLC patients. In total, we have found only 1 erbB2 mutation from 122 (0.8%) Japanese NSCLC patients. There was a significantly higher erbB2 positive (21/31) ratio in EGFR mutant patients (13/25, 52.0%) compared to EGFR wild-type patients (10/ 62, 16.1%; p 5 0.0247). The NSCLC specimen with erbB2 mutation showed 11 immunoreactivity. The EGFR mutation status might correlate with the clinicopathologic features related to good response to gefitinib, such as gender, smoking history and pathologic subtypes of lung cancers. However, erbB2 mutation is rare from Japanese lung cancer and is of limited value for molecular target therapy. ' 2005 Wiley-Liss, Inc.Key words: EGFR; lung cancer; mutations; erbB2; Japanese Lung cancer is a major cause of death from malignant diseases, due to its high incidence, malignant behavior and lack of major advancements in treatment strategy.1 Lung cancer was the leading indication for respiratory surgery (42.2%) in 1998 in Japan.2 More than 15,000 patients underwent surgical operations at Japanese institutions in 1998. 2 The clinical behavior of the lung cancer is largely associated with its stage. ...