title: HD-PTP and Alix share some membrane-traffic related proteins that interact with their Bro1 domains or proline-rich regions.
abstract: Mammalian Alix is a multifunctional adaptor protein involved in cell death, receptor endocytosis, endosomal protein sorting and cell adhesion by associating with various proteins such as ALG-2, CIN85/Rukl/SETA, endophilins, CHMP4s and TSG101. HD-PTP is a paralog of Alix and a putative protein tyrosine phosphatase (PTP) that contains a Bro1 domain, coiled-coils, a proline-rich region (PRR) in addition to a PTP domain. We investigated interactions between HD-PTP and Alix-binding proteins. In the yeast two-hybrid assay, HD-PTP showed positive interactions with CHMP4b/Shax1, TSG101, endophilin A1 and ALG-2 but not with either RabGAPLP or CIN85. We confirmed the interactions in a mammalian system by Strep-pulldown assays in which pulldown products from the lysates of HEK293T cells expressing either Strep-tagged HD-PTP alone or co-expressing with epitope-tagged proteins were analyzed by Western blotting using specific antibodies. While Alix associated with both ALG-2 and TSG101 in a Ca2+-dependent manner, HD-PTP interacted with ALG-2 Ca2+-dependently but with TSG101 Ca2+-independently.
authors.affiliation: Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Ichioka
authors.forename: Emi
authors.initials: E
authors.lastname: Takaya
authors.forename: Hironori
authors.initials: H
authors.lastname: Suzuki
authors.forename: Sachiko
authors.initials: S
authors.lastname: Kajigaya
authors.forename: Vladimir L
authors.initials: VL
authors.lastname: Buchman
authors.forename: Hideki
authors.initials: H
authors.lastname: Shibata
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Maki
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism; D056827:Endosomal Sorting Complexes Required for Transport; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism*; D011392:Proline / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D054558:Protein Tyrosine Phosphatases, Non-Receptor; D014157:Transcription Factors / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D000099177:Tsg101 Protein
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; D002118:Calcium; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D026901:Membrane Transport Proteins; D011392:Proline; D017027:Protein Tyrosine Phosphatases; D054558:Protein Tyrosine Phosphatases, Non-Receptor; D014157:Transcription Factors; D000099177:Tsg101 Protein; C478397:CHMP4B protein, human; C117020:PDCD6IP protein, human; C107640:SH3GL2 protein, human; C114102:PTPN23 protein, human