Tom Rapoport (Harvard, HHMI) 2: How are cellular organelles shaped?

[@medicinefuture]

your work is really great, I am fond of your work, I want to know about the molecular mechanics, how molecules move to the target, what makes them move,

[@TheZenytram]

through a lot of different mechanism, endoplasmic reticulum ER, diffusion, change in temperature, through hydrophobic molecule, by microtubule with kinesin and dynein, by actin with myosin, a whole bunch of ways, keep digging in the iBiology channel and you with find out.

[@medicinefuture]

​@@TheZenytram Dear I think it is not simple as you explained, for example, if a protein is needed by A mitochondria it will be synthesized by ribosome and it will be sent to this mitochondria, how the ribosome or DNA in the nucleus at first knows that a mitochondria need that protein and how the protein was sent specifically to this mitochondria to replenish the lost component, you have here space-time arrangement, and do not tell me that a signal was sent , there are millions or more substances dissolved and undissolved in the cytoplasm which is so difficult to transmit a chemical signal in such a medium without distortion of that signal, chemistry here cannot explain.

[@maverickross-girard7630]

@@medicinefuture When a protein concentration is low, the lack of the protein may activate or inhibit other proteins, thus propagating a signal like a game of Chinese whispers with great efficacity. The lack of the protein may activate the transcription from DNA to RNA of the protein's code and then the translation from RNA to the polypeptidic chain/protein. You might enjoy reading Molecular Biology of the Cell from Garland Science. There is information about signalisation.

[@eleonoraparra3672]

phys.org/news/2019-07-protein-sensing-mechanism.html life is still a huge mystery :)

[@mmartin5816]

Fantastic talk about a poorly understood phenomena. Still, I wonder what role cytoskeletal proteins play in the organization of the ER. How are mRNAs spatially localized to specific locations within the ER and the cell?

[@FabianRomano1]

Hi Martin. The microtubule cytoskeleton is not essential to form an ER network. You can start an in vitro ER formation reaction (xenopus egg extract), in the presence or absence of Nocodazol so no microtubules are present, and ER formation happens efficiently in both cases. That was part of the supplemental data on the 2013 JCB paper cited in the presentation. The cytoskeleton definitely plays a role in organizing and distributing the ER within cells though, there's plenty of evidence for that. Cheers.

[@medicinefuture]

here you don't show how the organelles formed, you just explained what happens, if you really want to show us- how- you must explain why this 3d shape(and not other) is formed like this what is the force which forms this shape

[@numericalcode]

Organelle research has an interesting history

[@InquilineKea]

ER tubules/sheets look NOTHING like how they're portrayed..

[@CandidDate]

One comment, this is all top-down analysis. What about bottom-up? From the basic form of a "vesicle" and what is contained in the vesicle, we can build all of the formations in the cell and body. I propose H2O is the primary vesicle, the female, and DNA is the primary male part. Veins and arteries are stacked vesicles, and blood is the primary male component. The digestive system is the primary female vesicle, and food and poop are the male components. ER is helical because it is a fractal of the DNA helix. DNA is the male and ribosomes are the female. Do you see what I'm getting at? Binary! It is all binary! Likewise, the lungs convert the male oxygen through the female structures into energy. The ER is the fractal lung of the cell. What is the primary function of the cell? Input and output. Input is the environment and energy, output is waste. The function of the cell is homeostasis. Bottom-up, we are all female and male components of the primary elements. Elements are carbon, nitrogen, oxygen, hydrogen, etc. Look into cellular automata for the way DNA is translated into female vesicles and male parts.

[@InquilineKea]

"tubules/positive membrane" are energetically unfavorable wow

[@magisgaming]

No

[@darinkamercado7662]

Por favor en español 😣

[@FabianRomano1]

Hola Darinka, soy Fabian Romano, autor de algunos de los papers en la presentacion. (Tom muestra experimentos mios entre 17:40 y 20:00). Voy a ofrecerme para hacer subtitulos en espanol ! (usando un teclado espanol por supuesto =) ). Gracias por comentar, Saludos !