The polyadenylation reaction passes through two stages. 

First, a rather short oligo(A) sequence (10 residues) is added to the 3’ end. This reaction is absolutely dependent on the AAUAAA sequence and poly(A) polymerase performs it under the direction of the specificity factor. 

In the second phase, the nuclear poly(A) binding protein (PABP II) binds the oligo(A) tail to allow extension of the poly(A) tail to the full 200 residue length.

TLS Online TPP Program

#Id: 1617

#Unit 4. Cell Communication and Cell Signaling

Humans CLRs that function as PRRs, most of which recognize one or more specific sugar moieties such as mannose (e.g., the mannose receptor and DC-SIGN), fucose (e.g., Dectin-2 and DC-SIGN), and glucans (e.g., Dectin-1).

TLS Online TPP Program

#Id: 1618

#Unit 4. Cell Communication and Cell Signaling

Chronic inflammation causes by IL-6, TNFα, IL-1β, IL-18.

TLS Online TPP Program

#Id: 1619

#Unit 4. Cell Communication and Cell Signaling

IL-10 and TGF-β regulate inflammation.

TLS Online TPP Program

#Id: 1620

#Unit 4. Cell Communication and Cell Signaling

TLR4 is unique in binding both MyD88 (when it is in the plasma membrane, signaling its endocytosis) and TRIF (when it is in endosomes, after internalization).

TLS Online TPP Program

#Id: 1621

#Unit 4. Cell Communication and Cell Signaling

COX2, whose synthesis is induced by PRR activation in monocytes, macrophages, neutrophils, and mast cells, is key to converting the lipid intermediate arachidonic acid to prostaglandins, potent proinflammatory mediators.

TLS Online TPP Program

#Id: 1622

#Unit 4. Cell Communication and Cell Signaling

IFN-α or -β activates IFNAR to recruit and activate specific JAKs (JAK1 and Tyk2), which then activate specific STATs induce expression of three genes, Protein kinase R (PKR), which inhibits viral (and cellular) protein synthesis by inhibiting the elongation factor eIF2α; 2’,5’-oligoadenlyate A synthetase, which activates the ribonuclease RNase L that degrades viral mRNA; and Mx proteins, which inhibit both the transcription of viral genes into mRNAs and the assembly of virus particles.