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#adaptor protein

3 public questions tagged with this topic.

Protein Sorting and Trafficking

Which adapter protein interacts with the NPXY motif of LDL receptors?

LDL receptor internalization requires highly specific recognition cytosolic tail by endocytic co-adaptors bridging to clathrin lattice enhancing efficiency. Tail 50 amino acids contains conserved FXNPXY motif positions 802-807 forming tight beta-turn favored aromatic phenylalanine tyrosine. PTB domains autosomal recessive hypercholesterolemia protein ARH LDLRAP1 and Dab2 Disabled-2 liver recognize NPXY tyrosine hydrophobic pocket interacting also basic residues upstream motif. Adaptors contain additional trafficking domains: clathrin box binding heavy chain terminal domain, AP2 beta2 appendage

Ref: He et al., Biochemistry: NPXY motif of LDLR binds ARH and AP2 adaptor.

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Immunology

MyD88 adaptor protein is used by

Most Toll-like receptors signal through the adaptor MyD88, which recruits IRAK kinases and ultimately activates NF-κB and MAP kinases. TLR3 and the endosomal form of TLR4 instead use the adaptor TRIF to activate IRF3 and type-I interferon production. The choice of adaptor therefore determines the balance between inflammatory and antiviral transcriptional programs.

Ref: NCERT Biology Class 11–12 Alberts et al Molecular Biology of the Cell Lodish et al, Molecular Cell Biology Cooper & Hausman, The Cell Abbas et al., Cellular and Molecular Immunology (for immunology sections)

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Cell Signaling ELR Pathways - I

Adaptor protein Grb2 contains which domain combination?

SH2 + SH3, is consistent with established principles of cell signaling, receptor pharmacology and cellular regulation. Experimental measurements of binding parameters, genetic loss-of-function studies and pharmacological interventions all converge on the same interpretation. Related options address neighboring concepts but do not satisfy the precise criterion stated in the question.

Ref: NCERT Biology Class 11–12 Alberts et al Molecular Biology of the Cell Lodish et al, Molecular Cell Biology Cooper & Hausman, The Cell Abbas et al., Cellular and Molecular Immunology (for immunology sections)

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