Identifikacija domena proteina IqgC potrebnih za njegovu regrutaciju na makropinosome u amebi Dictyostelium discoideum

master's thesis

• Title (english): Identification of IqgC domains required for its recruitment to macropinosomes in amoeba Dictyostelium discoideum
• Author: Petra Bajt
• Mentor: Vedrana Filić Mileta (mentor)
• Committee member: Aleksandra Maršavelski (predsjednik povjerenstva)
• Committee member: Željka Soldin (član povjerenstva)
• Committee member: Iva Juranović Cindrić (član povjerenstva)
• Committee member: Morana Dulić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2020-10-20, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

Protein IqgC iz amebe Dictyostelium discoideum spada u obitelj proteina IQGAP. Dosadašnja istraživanja su pokazala da IqgC, za razliku od drugih proteina IQGAP, ima sačuvanu GAP (engl. GTPase activating protein) aktivnost odnosno da može stimulirati GTP-hidrolitičku aktivnost male GTPaze RasG. Nadalje, pokazano je da je deaktivacija RasG pomoću IqgC važna za regulaciju unosa tekućine (makropinocitoza) i čestica (fagocitoza) tijekom hranjenja ove amebe te da IqgC lokalizira na membranu endosoma tijekom oba procesa. U ovom radu je ispitan doprinos pojedinih regija/domena proteina IqgC njegovoj regrutaciji na makropinosom. U tu svrhu eksprimirane su tri skraćene varijante proteina koje su sadržavale (1) samo GRD (engl. GAP related domain) domenu, (2) samo RGCt (engl. Ras-GAP-C_terminus) domenu i (3) GRD domenu i N-kraj proteina. Analiza lokalizacije ovih domena u živim stanicama deficijentnim za IqgC upotrebom konfokalne mikroskopije pokazala je da nijedna od njih nije dovoljna za lokalizaciju IqgC na membranu endosoma tijekom makropinocitoze.

Abstract (english)

Dictyostelium discoideum IQGAP-related protein IqgC is an atypical member of IQGAP protein family. Namely, recent study demonstrated that IqgC has conserved GAP (GTPase activating protein) activity and can deactivate Ras protein, while other IQGAP proteins have lost this activity due to mutations in their GRD (GAP related domain). IqgC exerts GAP activity toward small GTPase RasG during liquid uptake or macropinocytosis and particle uptake or phagocytosis, and thus negatively regulates RasG activity during both types of large-scale endocytosis. Moreover, full-length IqgC localizes to both macropinosomes and phagosomes. Using confocal microscopy, we have investigated the subcellular localization of truncated IqgC variants expressed as fluorescent protein fusions in iqgC knock-out cells. We showed that neither of the tested constructs, GRD alone, RGCt (Ras-GAP-C_terminus) domain alone and GRD with adjacent N-terminus, are sufficient for the recruitment of IqgC to endosomal membrane during macropinocytosis.

• Keywords: Dictyostelium; IQGAP; IqgC; makropinocitoza; RasGAP
• Keywords (english): Dictyostelium; IQGAP; IqgC; macropinocytosis; RasGAP
• Language: croatian
• URN:NBN: urn:nbn:hr:217:744634
• Study programme: Title: Graduate university studies in chemistry; specializations in: Research programme; Course: Research programme; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra kemije (magistar/magistra kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-10-28 13:18:12