Editing Nucleoplasm (section)

=== Proteins ===
There are around 20,000 [[protein-coding genes]] in humans,<ref name="Genome">{{cite web |title=Gene |url=https://www.genome.gov/genetics-glossary/Gene#:~:text=And%20genes%20are%20the%20part,of%20the%20entire%20human%20genome. |website=www.genome.gov |access-date=7 January 2025 |language=en}}</ref> and nearly a third of these have been found to  localize to the nucleoplasm via targeting by a [[nuclear localization sequence]] (NLS).<ref name="proteinatlas_nucleoplasm"/> Cytosolic proteins, known as [[importin]]s, act as receptors for the NLS, escorting the protein to a nuclear pore complex to be transported into the nucleoplasm.<ref name=":3">{{cite book |last=Casem|first=Merri Lynn|date=2016 |title=Case Studies in Cell Biology |publisher=Elsevier|pages=73–103 |isbn=978-0-12-801394-6}}</ref> Proteins in the nucleoplasm are mainly tasked with participating in and regulating cellular functions that are DNA-dependent, including transcription, [[RNA splicing]], [[DNA repair]], [[DNA replication]], and a variety of metabolic processes.<ref name="proteinatlas_nucleoplasm"/> These proteins are divided into histone proteins, a class of proteins that bind to DNA and give chromosomes their shape and regulate gene activity,<ref>{{cite journal |last1=Stein |last2=Thrall |first2=C.L. |date=1973|title=Evidence for the presence of nonhistone chromosomal proteins in the nucleoplasm of HeLa S3 cells |journal=FEBS Letters |volume=32 |issue=1 |pages=41–45 |doi=10.1016/0014-5793(73)80732-X|pmid=4715686 |s2cid=20285491 |doi-access=free }}</ref> and non-histone proteins.

The nucleoplasm contains many enzymes that are instrumental in the synthesis of DNA and RNA, including [[DNA polymerase]] and [[RNA polymerase]] which function in DNA replication and RNA transcription, respectively. Additionally, the nucleoplasm is host to many of the enzymes that play essential roles in [[cellular metabolism]]. [[NAD+ synthase]] is stored in the nucleoplasm and functions in electron transport and [[redox reaction]]s involved with the [[electron transport chain]] and synthesis of [[adenosine triphosphate]] (ATP).<ref>{{cite journal |last1= Houtkooper |last2= Cantó |first2=C. |last3=Wanders |first3=R.J. |last4= Auwerx |first4=J. |date=2010|title=The Secret Life of NAD+: An Old Metabolite Controlling New Metabolic Signaling Pathways |journal= Endocrine Reviews|volume=31 |issue=2 |pages=194–223 |doi=10.1210/er.2009-0026|pmid= 20007326 |pmc= 2852209 }}</ref> [[Pyruvate kinase]] is also found in the nucleoplasm in significant quantities; this enzyme is involved in the final step of [[glycolysis]], catalyzing the conversion of [[phosphoenolpyruvate]] (PEP) to [[pyruvate]] along with the phosphorylation of [[adenosine diphosphate]] (ADP) to ATP.<ref>{{cite journal |last1= Israelsen |last2= Vander Heiden |first2=M.G. |date=2015|title=Pyruvate kinase: Function, regulation and role in cancer |journal=Seminars in Cell & Developmental Biology |volume=43 |pages=43–51 |doi=10.1016/j.semcdb.2015.08.004|pmid= 26277545 |pmc= 4662905 }}</ref> Importantly, the nucleoplasm contains [[Cofactor (biochemistry)|co-factor]]s and co-enzymes, including [[acetyl-CoA]], which plays a vital role in the [[citric acid cycle]],<ref>{{cite journal |last1=Falcón |last2=Chen |first2=S. |last3=Wood |first3=M.S. |last4=Aris |first4=J.P.|date=2010 |title=Acetyl-coenzyme A synthetase 2 is a nuclear protein required for replicative longevity in Saccharomyces cerevisiae |journal=Molecular and Cellular Biochemistry |volume=333 |issue=1–2 |pages=99–108 |doi=10.1007/s11010-009-0209-z|pmid=19618123 |pmc=3618671 }}</ref> and ATP, which is involved in energy storage and transfer.