title: The catalytic region and PEST domain of PTPN18 distinctly regulate the HER2 phosphorylation and ubiquitination barcodes.
abstract: The tyrosine phosphorylation barcode encoded in C-terminus of HER2 and its ubiquitination regulate diverse HER2 functions. PTPN18 was reported as a HER2 phosphatase; however, the exact mechanism by which it defines HER2 signaling is not fully understood. Here, we demonstrate that PTPN18 regulates HER2-mediated cellular functions through defining both its phosphorylation and ubiquitination barcodes. Enzymologic characterization and three crystal structures of PTPN18 in complex with HER2 phospho-peptides revealed the molecular basis for the recognition between PTPN18 and specific HER2 phosphorylation sites, which assumes two distinct conformations. Unique structural properties of PTPN18 contribute to the regulation of sub-cellular phosphorylation networks downstream of HER2, which are required for inhibition of HER2-mediated cell growth and migration. Whereas the catalytic domain of PTPN18 blocks lysosomal routing and delays the degradation of HER2 by dephosphorylation of HER2 on pY(1112), the PEST domain of PTPN18 promotes K48-linked HER2 ubiquitination and its rapid destruction via the proteasome pathway and an HER2 negative feedback loop. In agreement with the negative regulatory role of PTPN18 in HER2 signaling, the HER2/PTPN18 ratio was correlated with breast cancer stage. Taken together, our study presents a structural basis for selective HER2 dephosphorylation, a previously uncharacterized mechanism for HER2 degradation and a novel function for the PTPN18 PEST domain. The new regulatory role of the PEST domain in the ubiquitination pathway will broaden our understanding of the functions of other important PEST domain-containing phosphatases, such as LYP and PTPN12.
authors: 1] Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong 250012, China [2] Department of Physiology, Shandong University School of Medicine, Jinan, Shandong 250012, China.
authors: Hong-Mei
authors: HM
authors: Wang
authors: 1] Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong 250012, China [2] Department of Physiology, Shandong University School of Medicine, Jinan, Shandong 250012, China.
authors: Yun-Fei
authors: YF
authors: Xu
authors: Qilu Hospital, Shandong University, Jinan, Shandong 250012, China.
authors: Shang-Lei
authors: SL
authors: Ning
authors: Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong 250012, China.
authors: Du-Xiao
authors: DX
authors: Yang
authors: Shandong Provincial Hospital, Shandong University, Jinan, Shandong 250021, China.
authors: Yi
authors: Y
authors: Li
authors: Department of Physiology, Shandong University School of Medicine, Jinan, Shandong 250012, China.
authors: Yu-Jie
authors: YJ
authors: Du
authors: Department of Physiology, Shandong University School of Medicine, Jinan, Shandong 250012, China.
authors: Fan
authors: F
authors: Yang
authors: Department of Physiology, Shandong University School of Medicine, Jinan, Shandong 250012, China.
authors: Ya
authors: Y
authors: Zhang
authors: 1] Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong 250012, China [2] Shandong Provincial Hospital, Shandong University, Jinan, Shandong 250021, China.
authors: Nan
authors: N
authors: Liang
authors: Department of Physiology, Shandong University School of Medicine, Jinan, Shandong 250012, China.
authors: Wei
authors: W
authors: Yao
authors: Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong 250012, China.
authors: Ling-Li
authors: LL
authors: Zhang
authors: Shandong University, School of Life Science, Jinan, Shandong 250012, China.
authors: Li-Chuan
authors: LC
authors: Gu
authors: Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong 250012, China.
authors: Cheng-Jiang
authors: CJ
authors: Gao
authors: Shandong Provincial Hospital, Shandong University, Jinan, Shandong 250021, China.
authors: Qi
authors: Q
authors: Pang
authors: Qilu Hospital, Shandong University, Jinan, Shandong 250012, China.
authors: Yu-Xin
authors: YX
authors: Chen
authors: Duke University, School of Medicine, Durham, 27705, USA.
authors: Kun-Hong
authors: KH
authors: Xiao
authors: Qilu Hospital, Shandong University, Jinan, Shandong 250012, China.
authors: Rong
authors: R
authors: Ma
authors: 1] Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong 250012, China [2] Department of Physiology, Shandong University School of Medicine, Jinan, Shandong 250012, China [3] Qilu Hospital, Shandong University, Jinan, Shandong 250012, China.
authors: Xiao
authors: X
authors: Yu
authors: 1] Key Laboratory for Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong 250012, China [2] Shandong Provincial Hospital, Shandong University, Jinan, Shandong 250021, China.
authors: Jin-Peng
authors: JP
authors: Sun
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology; D020134:Catalytic Domain; D045744:Cell Line, Tumor; D018360:Crystallography, X-Ray; D005260:Female; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008239:Lysine / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D009367:Neoplasm Staging; D010455:Peptides / Q000378:metabolism; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D054558:Protein Tyrosine Phosphatases, Non-Receptor / Q000737:chemistry* / Q000378:metabolism*; D059748:Proteolysis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D015398:Signal Transduction; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D054875:Ubiquitination; D044844:beta-Transducin Repeat-Containing Proteins / Q000378:metabolism
chemical_list: D008239:Lysine; D010455:Peptides; D019000:Phosphotyrosine; D046988:Proteasome Endopeptidase Complex; D054558:Protein Tyrosine Phosphatases, Non-Receptor; D018719:Erb-b2 Receptor Tyrosine Kinases; D044844:beta-Transducin Repeat-Containing Proteins; C508053:ERBB2 protein, human; C422224:PTPN18 protein, human