Sandbox 122: Difference between revisions
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Karyopherinβ is a group of proteins that is composed of both importins and exportins. Importins are proteins that carry cargos into the nucleus while exportins serve the opposite function. As of today, twenty different Kapβs have been identified. Each of these Kapβs is capable of recognizing and transporting a specific group of cargos. In order to bind to its cargo a Kapβ has to recognize a Nuclear Localization or Export Signal (NLS or NES). | Karyopherinβ is a group of proteins that is composed of both importins and exportins. Importins are proteins that carry cargos into the nucleus while exportins serve the opposite function. As of today, twenty different Kapβs have been identified. Each of these Kapβs is capable of recognizing and transporting a specific group of cargos. In order to bind to its cargo a Kapβ has to recognize a Nuclear Localization or Export Signal (NLS or NES). | ||
Karyopherin beta 2 (kapβ2) is an importin that transports various cargo protein into the nucleus through interactions with nucleoporins, which are proteins of the nucleopore complex (NPC). One might overlook the significance of this protein but actually plays a crucial role in the human body by mediating transport of RNA- binding proteins involved in transcription, RNA processing, RNA transport and translation. The structure of KAPβ is composed of <scene name='37/372723/4oo6_rainbow_heat_repeats/1'>20 antiparallel helices </scene>called [https://en.wikipedia.org/wiki/HEAT_repeat_domain HEAT]repeats. These HEAT repeats contribute to kapβ2’s large superhelical shape. That form two arches:one at the <scene name='37/372723/4oo6_ran_binding_site/2'>N-Terminal</scene>and the other at the | Karyopherin beta 2 (kapβ2) is an importin that transports various cargo protein into the nucleus through interactions with nucleoporins, which are proteins of the nucleopore complex (NPC). One might overlook the significance of this protein but actually plays a crucial role in the human body by mediating transport of RNA- binding proteins involved in transcription, RNA processing, RNA transport and translation. The structure of KAPβ is composed of <scene name='37/372723/4oo6_rainbow_heat_repeats/1'>20 antiparallel helices </scene>called [https://en.wikipedia.org/wiki/HEAT_repeat_domain HEAT]repeats. These HEAT repeats contribute to kapβ2’s large superhelical shape. That form two arches:one at the <scene name='37/372723/4oo6_ran_binding_site/2'>N-Terminal</scene> and the other at the | ||
<scene name='37/372723/4oo6_substrate_binding_side/2'>C-Terminal</scene> Through recognition of a nuclear localization signal (NLS) located on its cargo, kapβ2 binds to its cargo via its C-terminal arch. Release of the cargo is mediated by RanGTP, which once bound, modifies the shape of kapβ2. Release of the cargo is mediated once contact occurs between RanGTP and N-terminal arch of Kapβ2. | <scene name='37/372723/4oo6_substrate_binding_side/2'>C-Terminal</scene> Through recognition of a nuclear localization signal (NLS) located on its cargo, kapβ2 binds to its cargo via its C-terminal arch. Release of the cargo is mediated by RanGTP, which once bound, modifies the shape of kapβ2. Release of the cargo is mediated once contact occurs between RanGTP and N-terminal arch of Kapβ2. | ||
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Recognition the PY-NLS by Kapβ2 follows a certain guidelines: | Recognition the PY-NLS by Kapβ2 follows a certain guidelines: | ||
#PY-NLS, when not bound to Kapβ2, lacks a secondary structure. | #PY-NLS, when not bound to Kapβ2, lacks a secondary structure. | ||
#PY-NLS hass an overall positive charge allowing for electrostatic compatibility with Kapβ2. | #PY-NLS hass an overall <scene name='37/372723/Positive_interaction_nls_only/3'>positive charge</scene> allowing for electrostatic compatibility with Kapβ2. | ||
#General sequence for the PY-NLS is either a hydrophobic or base at the motif at N-terminus and R-X2-5- P-Y motif at the C-terminus | #General sequence for the PY-NLS is either a hydrophobic or base at the motif at N-terminus and R-X2-5- P-Y motif at the C-terminus | ||