The Golgi apparatus is one of the microtubule organizing centers in mammalian cells that regulate the noncentrosomal microtubule to plays essential roles in Golgi organization, Golgi morphogenesis, polarized transport, cell motility, and cell differentiation. However, the control mechanism of Golgi-derived microtubule remains indefinable. Recently, a proposed model depicted that minus end of Golgi-derived microtubule is anchored and stabilized by a protein complex composed by GM130, AKAP450, myomegalin, CAMSAP2 and CLASPs. Most of these proteins are end binding proteins (EB) partners, GAS2L1 was identified as an new EB partner by mass spectrometer. GAS2L1, a microtubule- and actin-binding protein, is involved in regulating microtubule and actin dynamic as well as regulating the...[ Read more ]

The Golgi apparatus is one of the microtubule organizing centers in mammalian cells that regulate the noncentrosomal microtubule to plays essential roles in Golgi organization, Golgi morphogenesis, polarized transport, cell motility, and cell differentiation. However, the control mechanism of Golgi-derived microtubule remains indefinable. Recently, a proposed model depicted that minus end of Golgi-derived microtubule is anchored and stabilized by a protein complex composed by GM130, AKAP450, myomegalin, CAMSAP2 and CLASPs. Most of these proteins are end binding proteins (EB) partners, GAS2L1 was identified as an new EB partner by mass spectrometer. GAS2L1, a microtubule- and actin-binding protein, is involved in regulating microtubule and actin dynamic as well as regulating the centrosome disjunction. Beside its Centrosomal activity, I reveal that GAS2L1 is involved in the regulation of Golgi reassembly and Golgi-derived microtubule growth. Using the CRISPR/CAS9 genome-editing method, I established GAS2L1 knockout cell lines and studied the molecular mechanism of Golgi assembly. Cells deficient of GAS2L1 showed defects in Golgi morphology and nocodazole washout-induced reassembly. Furthermore, I found that Golgi-derived microtubule regrowth after nocodazole washout was inhibited in the knockout cells. To reveal the detail mechanism by which GAS2L1 regulates Golgi-derived microtubules, we screened for GAS2L-associated proteins by a biochemical approach and identified CLASP1/2, which have known functions in the regulation of Golgi-derived microtubules not only at minus end but also at microtubule lattice and plus end. To conclude the findings, I suggest that GAS2L1 is important for Golgi assembly and structural organization by forming functional complexes with CLASPs to stabilize whole Golgi-derived microtubules.