Xic is a cis-acting locus that contains the information necessary to count X chromosomes and inactivate all copies but one. Inactivation spreads from Xic along the entire X chromosome.

TLS Online TPP Program

#Id: 10026

#Unit 4. Cell Communication and Cell Signaling

NF-κB pathway is activated by:

TNFα and IL-1, released by immune cells in response to infection.

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#Id: 10027

#Unit 4. Cell Communication and Cell Signaling

NF-κB stimulates expression of several anti-apoptotic proteins, including FLIP, Bcl-XL, A1/Bfl-1, c-IAP, XIAP, TRAF1, and TRAF2.

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#Id: 10028

#Unit 4. Cell Communication and Cell Signaling

In certain immune cells, NF-κB stimulates expression of iNOS (inducible isoform of the enzyme that produces NO), which is toxic to bacterial cells

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#Id: 10029

#Unit 4. Cell Communication and Cell Signaling

In resting cells,

NF-κB binds directly to an inhibitor called I-κBα

TLS Online TPP Program

#Id: 10030

#Unit 4. Cell Communication and Cell Signaling

A single molecule of I-κBα binds to N-terminal domains of the p50–p65 subunits, masking their NLS.

TLS Online TPP Program

#Id: 10031

#Unit 4. Cell Communication and Cell Signaling

I-κB kinase 

three-protein complex and is responsible for releasing NF-κB from sequestration