title: Sorting nexin 17, a non-self-assembling and a PtdIns(3)P high class affinity protein, interacts with the cerebral cavernous malformation related protein KRIT1.
abstract: The mammalian sorting nexin (SNX) proteins are involved in the endocytosis and the sorting machinery of transmembrane proteins. Additionally to the family defining phox homology (PX) domain, SNX17 is the only member with a truncated FERM (4.1, ezrin, radixin, and moesin) domain and a unique C-terminal region (together designated as FC unit). By gel filtration and lipid overlay assays we show that SNX17 is a non-self-assembling and a PtdIns(3)P high class affinity protein. A SNX17 affinity to any other phosphoinositides was not detected. By yeast two-hybrid- and GST-trapping assays we identified KRIT1 (krev1 interaction trapped 1) as a new specific interaction partner of the FC unit of SNX17. KRIT1 binds SNX17 by its N-terminal region like the known interaction partner ICAP1alpha (integrin cytoplasmic domain-associated protein-1). The interaction was also detected in HEK 293 cells transiently expressing GFP-tagged KRIT1 and Xpress-tagged SNX17. KRIT1 mutations cause cerebral cavernous malformation (CCM1). Our finding suggests a SNX17 involvement in the indicated KRIT1 function in cell adhesion processes by integrin signaling.
authors.affiliation: Institut für Biochemie, Medizinische Fakultät, Otto-von-Guericke-Universität, Leipziger Str. 44, 39120 Magdeburg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Czubayko
authors.forename: Peter
authors.initials: P
authors.lastname: Knauth
authors.forename: Thomas
authors.initials: T
authors.lastname: Schlüter
authors.forename: Volker
authors.initials: V
authors.lastname: Florian
authors.forename: Ralf
authors.initials: R
authors.lastname: Bohnensack
mesh_terms: D002352:Carrier Proteins / Q000737:chemistry / Q000502:physiology*; D002450:Cell Communication; D002850:Chromatography, Gel; D042783:Endothelial Cells / Q000166:cytology; D005978:Glutathione / Q000378:metabolism; D020786:Hemangioma, Cavernous, Central Nervous System / Q000378:metabolism; D006801:Humans; D016023:Integrins / Q000378:metabolism; D000075927:KRIT1 Protein; D007700:Kinetics; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000737:chemistry*; D010716:Phosphatidylinositols / Q000737:chemistry; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D058305:Sorting Nexins; D020798:Two-Hybrid System Techniques; D033921:Vesicular Transport Proteins
chemical_list: D002352:Carrier Proteins; D016023:Integrins; D000075927:KRIT1 Protein; C107928:KRIT1 protein, human; D008869:Microtubule-Associated Proteins; D010716:Phosphatidylinositols; D011518:Proto-Oncogene Proteins; C487895:SNX17 protein, human; D058305:Sorting Nexins; D033921:Vesicular Transport Proteins; D019869:Phosphatidylinositol 3-Kinases; D005978:Glutathione