Diphtheria Toxin Action Mechanism | Signalling Pathway

Diphtheria toxin is an exotoxin secreted by Corynebacterium, the pathogenic bacterium that causes diphtheria.
Diphtheria toxin is composed of two subunits bound by a disulfide bond between cysteine residues: the amino-terminal A-subunit contains the catalytic (C) domain (not shown), and the carboxyl-terminal B-subunit contains a membrane-inserting translocation (T) domain and a receptor-binding (R) domain (not shown). Diphtheria toxin secreted from the bacterial cell binds to the proheparin-binding epidermal growth factor-like growth factor (HB-EGF), which acts as a DT receptor. DT enters the cell via receptor-mediated endocytosis through clathrin-coated pits: the R domain recognizes the HB-EGF receptor on human epithelial cells, leading to endocytosis of the entire receptor-toxin complex. Endosome-associated proteases partially cleave the bond between the DT subunits, and exposure of the DT to the acidic conditions triggers a conformational change that enables the T domain to insert into the endosome membrane and the subsequent translocation of the A-subunit across the endosomal membrane into the cytosol. The T domain is thought to be primarily responsible for membrane insertion, although the C and R domains have also been shown to be associated with membranes262. In the cytosol, the C domain catalyses the transfer of the ADP-ribose moiety of nicotinamide adenine dinucleotide (NAD) onto the elongation factor 2 (EF-2). EF-2 is a member of the GTP-binding translation elongation factor family. This protein is an essential factor for the cell protein synthesis and enables the transfer of the peptidyl tRNA-mRNA complex from the ribosome to the peptidyl site during protein synthesis. DT targets a post-transcriptionally modified histidine diphthamide on EF-2 (ref.263). ADP-ribosylation of this unique diphthamide residue prevents EF-2 translocation activity, resulting in inhibition of protein production.

[@michaeleisenberg7867]

Hello Shabir, No one can draw a lipid bilayer as quickly and accurately as you. I love 💕 it. Plus an old friend & an inexplicable marvel of evolution, the V-ATPase proton pump complete with stator subunits strapping it together, makes an appearance. This video has it all--pop and sizzle ⚡✨! Thank you. 👏👏👏🎈🎈🎈

[@hussainbiology]

thanks Dr. Mike for appreciation.. the VATPase is marvelous molecule....

[@michaeleisenberg7867]

@@hussainbiology Shabir, I was reading about epochs. It took 500M yrs for the earth to cool enough to start evolution. Then 500M yrs to form the first archean bacteria. Then 3B yrs to evolve multicellular organisms. Finally, in the last 500M yrs evolution went from sponges and trilobites to us! What surprises me the most is it took only 500M yrs to form one cell but 3B yrs to connect a bunch together.

[@blessedsoul4216]

Amazingly explained

[@hussainbiology]

Glad you liked it

[@mohammedriad6257]

This is amazing!!

[@aamirhussain.]

❤❤❤

[@important108]

Hey! Mr. Hussain nice explanation and nice voice

[@hussainbiology]

thanks buddy....👍

[@aamirhussain.]

Respected sir❤..
one lecture on Tumur suppresor genes .

[@hussainbiology]

Okay brother... very soon

[@priyankaswami6552]

Am not the first who comment here... Got late..

[@aaqibhameed2972]

❤️❤️👍

[@Sanus-anime-world]

5 years ago you posted a video about "End replication problem" , "telomerase replication" , I'm having a doubt understanding about the leading strand primer removal.. so here's the thing..
I'm confused here brother, the leading strand is also synthesized by primer, so when the primer is removed from the leading strand, how the dna in that portion is replicated, because there's no 3'OH group when the primer is removed from the leading strand, it should also be smaller than the parental DNA, so can you please tell me, it'd be very much helpful to me.

[@Shabirdar112]

at 1:33min in that video , when strands open for replication in eukaryote only the upper strand is the leading stand .. rest u can see the discussion in the pinned comments where the mistake is

[@Sanus-anime-world]

@@Shabirdar112 no no, I get that, but the problem is in the lagging strand, in order to replicate the genomic dna the strand gets elongated by telomerase, but in the leading strand what happens to the first primer when it is removed from there, how it replicates the portion of the dna, does it get elongated by telomerase aslo ?!

[@GOODTOBEABLE]

Which app r u using please?

[@hussainbiology]

Final Cut Pro

[@Khana_PakhanawithMehwish]

👍

[@nabeelawan5280]

Sir what is your mail id? i wanna ask something.. ALLAH BLESS YOU..

[@hussainbiology]

[e-mail]

[@nabeelawan5280]

@@hussainbiology sir i sent you a mail.. kindly reply JAZAKALLAH

[@learningpointexpert9667]

@@hussainbiology sir how you record your videos.. I m very inspired from you.. kindly do reply.. ALLAH BLESS YOU

[@nabeelawan5280]

@@hussainbiology sir kindly reply .. JAZAKALLAH

[@hussainbiology]

@@nabeelawan5280 will write to you in the evening