Ubiquitination Exam AAMC Q Spoiler

[ArtsyArtist25]

I am honestly a little confused with this question. Why can't it be C?? In Cell S&F I learned that ubiquitination targets a cell protein for lysosomal destruction via protease enzymes. I mean I get why A can be correct but why not C?

 

[Lawpy]

I'm pretty sure the lysosome pathway is used to degrade/recycle plasma membrane proteins, such as receptors and channels.

This review gives a pretty good overview on the different ubiquitin pathways: Ubiquitin: Same Molecule, Different Degradation Pathways

 

[ArtsyArtist25]

I'm pretty sure the lysosome pathway is used to degrade/recycle plasma membrane proteins, such as receptors and channels.

This review gives a pretty good overview on the different ubiquitin pathways: Ubiquitin: Same Molecule, Different Degradation Pathways

Sorry, I did mean to say cellular proteins.
Thank you very much though for the paper!

 

[MedSchoolTutors]

Yeah this is just testing if you understand that without Wnt, B catenin is bound and ubiquitinated and that Ubq chops up proteins for degradation and recycling. Interestingly enough, this is a pathway seen sometimes in colon cancer, where Wnt is mutated and perpetually active. This leads to B-Catenin causing uncontrolled cellular differentiation and neoplasia.

David D, MD - USMLE and MCAT Tutor
Med School Tutors

 

[ArtsyArtist25]

Yeah this is just testing if you understand that without Wnt, B catenin is bound and ubiquitinated and that Ubq chops up proteins for degradation and recycling. Interestingly enough, this is a pathway seen sometimes in colon cancer, where Wnt is mutated and perpetually active. This leads to B-Catenin causing uncontrolled cellular differentiation and neoplasia.

David D, MD - USMLE and MCAT Tutor
Med School Tutors

Huh, I didn't know that. I feel like I learn so much from the science res. passages every time I do practice!

 

[MedSchoolTutors]

Huh, I didn't know that. I feel like I learn so much from the science res. passages every time I do practice!

Honestly, as someone who took the 'old' MCAT in 2013 and has spent 7 years in the tutoring game, that is one of my favorite changes with the 2015+ MCAT, there is so much clinical relevance in it. I encourage you whenever you feel curious, to read on the topic. It need not be much, a Wikipedia page will suffice, but you will encode the material so much stronger once it becomes 'real'. Once, I was teaching a Khan Academy passage and it hit me, this was the 'original' study determining why ACEs cause chronic cough and ARBs don't. So cool. Happy studying!

David D, MD - USMLE and MCAT Tutor
Med School Tutors