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b'The protein GMAP-210 (Golgi Microtubule Associated Protein of 210 kDa) is a long\\ncoiled-coil protein, which localises to the Golgi apparatus. It is part of the loosely defined\\nprotein group of the golgins, which are involved in establishing the Golgi morphology and\\nin vesicular trafficking around the Golgi.\\nBy using biochemical, cell biological and molecular biological methods GMAP-210 was\\nexamined in regards to its Golgi targeting capability, its interaction partners and its function\\nin establishing Golgi morphology and positioning.\\nIn vitro and in vivo experiments showed that GMAP-210 targets to the Golgi via its\\nC-terminal GRAB domain. Its proposed interaction with Arf1, however, could not be\\ndefinitely determined, although there is strong evidence for it. Arf1 binding to the GRAB\\ndomain was hindered in the full-length protein, but not with short C-terminal fragments\\ncontaining the minimal GRAB domain. This implies that additional factors are needed\\nfor GMAP-210 Golgi binding.\\nA yeast 2-hybrid screen of the entire family of small Rab GTPases identified the Golgi and\\nER localised Rab1 as a novel interaction partner of GMAP-210. GMAP-210 also labels\\nvesicular tubular structures in the cell, which partially overlap with COPII and ERGIC53,\\ncomponents of the early secretory pathway. This gives additional evidence that GMAP-\\n210 is involved in ER to Golgi transport. Trafficking of a model substrate, the vesicular\\nstomatitis virus G-protein (VSV-G), however, was not impaired in the absence of GMAP-\\n210. This indicates that GMAP-210 functions only in specialised transport pathways.\\nKnockdown of GMAP-210 in HeLa L cells by siRNA changed the Golgi morphology and\\nthe Golgi fragmented into a cluster of vesicles. Its overexpression caused the Golgi to grow\\nlong tubular structures. Both effects on morphology could only be observed in HeLa L\\ncells, not in hTERT-RPE1 cells. As direct interaction with microtubules or \\u03b3-tubulin\\ncould not be detected, and GMAP-210 is therefore unlikely to affect Golgi morphology\\nby directly perturbing microtubule function.\\nGMAP-210 knockdown by siRNA also showed its interaction with the intraflagellar transport\\nprotein IFT20. This protein lost its Golgi localisation when GMAP-210 was depleted.\\nBoth proteins interacted directly. GMAP-210, however, was not involved in primary cilium\\nformation in hTERT-RPE1 cells and loss of IFT20 from the Golgi did not impair\\nformation of the cilium, proposing that the Golgi pool of IFT20 had a function apart from\\nintraflagellar transport and formation of the primary cilium.\\nThese results set GMAP-210 apart from the archetypal golgins GM130 and p115 and indicate\\nthat GMAP-210 is involved in a highly specialised transport pathway, which could\\nnevertheless influence the morphology of the Golgi apparatus in certain cell types.'