RNA localization mRNA can be localized to subcellular compartments by actin or tubulin-dependent processes Examples: Xenopus: Vg1 mRNA (TGF  ) to vegetal.

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RNA localization mRNA can be localized to subcellular compartments by actin or tubulin-dependent processes Examples: Xenopus: Vg1 mRNA (TGF  ) to vegetal pole Drosophila: nanos, oskar mRNA (posterior) and bicoid (anterior) (requires mRNA binding protein staufen) (requires staufen and miranda) prospero (into ganglion of mother cells; neuroblast TF) Yeast: Ash1 mRNA to daughter cell

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Type III membrane proteins have internal signal sequence

Type II+III membrane proteins have internal signal sequences

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Translocation of proteins with multiple membrane spanning domains

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Summary ER translocation: SRP-dependent and -independent pathways; translocation occurs through Sec61 complex; topogenic sequences determine overall orientation. ER function Compartmental identity: maturation versus fixed compartments Identification of components: combination of genetics, biochemistry... Vesicular coats: COPI ~ retrograde: Golgi->ER COPII ~anterograde: ER->Golgi CCV post-Golgi, various adaptors