Biomedical Engineering Reference
In-Depth Information
perform.RNA.splicing,.manage.protein.degradation.by.the.proteasome,.establish.chemical.
and.energy.gradients,.and.dramatically.reorganize.the.cellular.infrastructure.on.demand..
The. latter. includes. reorganization. of. dynamic. polymeric. chains. of. actin. and. microtu-
bules.from.multifunctional.scaffolds.to.functionally.speciic.structures.such.as.the.bipolar.
spindle. and. cytokinetic. ring.. The. cell. is. evolutionary. perfection. of. a. highly. responsive.
quantum-nano-microscale.system.that.is.itself.further.scalable.into.tissues,.organs,.organ-
isms,.and.communities.of.organisms..Within.a.cell,.multiple.signaling.pathways.can.run.
as. distinct,. autoregulated,. parallel,. or. interlinked. cascades. with. feedback. loops. to. inte-
grate. several. processes.. Through. the. dissection. and. harnessing. of. biological. machines.
and. underlying. processes,. and. their. subsequent. merger. with. synthetic. materials,. we.
hope. to. scale. manufacturing. into. realms. that. currently. remain. restricted. from. physical.
manipulation.
The. depth. in. which. we. understand. a. mechanism. is. best. determined. through. the.
isolation.of.components.and.their.reconstitution.that.veriies.that.all.elements.necessary.
to.fully.recapitulate.the.process.are.in.hand..Multiple.challenges.underlie.biomimicry.of.
intracellular. machines.. For. those. that. are. largely. protein. based,. how. communication. is.
relayed.within.a.single.protein.and.between.proteins.in.a.complex.is.still.only.supericially.
understood..Protein-protein.interactions.are.often.inluenced.by.multisite.protein.chemical.
modiications. such. as. phosphorylation,. glycosylation,. ubiquitination,. tyrosination,. and.
more..Such.modiications.can.create.conformational.changes,.redirect.protein.localization,.
enable. or. block. protein-protein. interactions,. and. stabilize. or. destabilize. proteins.. In.
nature,.this.generates.an.ability.to.either.optimize.a.system.or.to.regulate.its.function.
We. have. only. skimmed. the. surface. in. appreciating. the. wealth. of. outcomes. from.
modifying. signaling. through. protein. interactions.. Layering. of. controls. through.
multiprotein.complexes.also.occurs.in.cells..An.example.of.this.is.the.use.of.checkpoint.
proteins. that. are. generally. not. part. of. a. mechanism. but. which. can. provide. dual. roles.
as. sensor. and. reversible. brake. (Hartwell. and. Weinert,. 1989).. This. allows. a. process. that.
incorporates.multiple.steps.to.stay.coordinated.when.any.one.step.is.delayed.or.irreparably.
fails.. Not. all. errors. are. correctable,. and. in. cells,. a. checkpoint. may. still. be. overridden.
depending.on.the.greater.essential.need.to.complete.the.process.for.survival..Localized.
chemical.gradients.provide.an.additional.capability.to.regulate.and,.in.many.cases,.supply.
an. artiicial. “containment”. parameter.. While. we. are. far. from. being. able. to. replicate. the.
regulatory. complexity. present. in. a. living. cell. or. organism,. we. have. begun. to. harness.
cellular.molecular.motors.as.pioneers.of.nanorobotics.and.nanoengineering..In.the.long.
term,. the. Holy. Grail. is. to. remove. ourselves. more. completely. from. the. process,. thereby.
allowing.self-assembling.mechanisms.to.proceed.under.minimal.guidance.
4.2 Molecular Motors: “Life Is Motion”
Humans,. as. a. species,. possess. an. innate. creative. aptitude. toward. problem. solving..
Decisions.to.explore.novel.solutions.or.reine.existing.methods.are.often.technologically.
dependent.. Perhaps,. the. greatest. discoveries. occur. both. through. the. application. of.
radical. and. enlightening. concepts. as. well. as. by. combining. distinct. technologies. and.
components. in. novel. ways.. In. terms. of. manufacturing,. familiar. needs. apply. that. are. to.
optimize. eficiency,. reduce. the. need. for. manual. labor,. or. to. allow. production. that. was.
previously.unfeasible.due.to.cost.or.capability..One.of.the.most.integrated.achievements.
