The directed movement of protons (hydrogen ions) into, out of, within or between cells.

The chemical reactions involving creatine (N-(aminoiminomethyl)-N-methylglycine), a compound synthesized from the amino acids arginine, glycine, and methionine that occurs in muscle.

The formation from simpler components of creatine (N-(aminoiminomethyl)-N-methylglycine), a compound synthesized from the amino acids arginine, glycine, and methionine that occurs in muscle.

The process of targeting specific proteins to particular membrane-bound subcellular organelles. Usually requires an organelle specific protein sequence motif.

The directed movement of a protein from the cytoplasm to the nucleus.

The directed movement of a protein bearing a nuclear localization signal (NLS) from the cytoplasm into the nucleus, across the nuclear membrane.

The chemical reactions involving macromolecules, large molecules including proteins, nucleic acids and carbohydrates, as carried out by individual cells.

The directed movement of a small nuclear ribonucleoprotein from the cytoplasm into the nucleus, across the nuclear membrane.

The smooth endoplasmic reticulum (ER) has with no ribosomes attached to it. The smooth is the recipient of the proteins synthesized in the rough ER. Those proteins to be exported are passed to the Golgi complex, the resident proteins are returned to the rough ER and the lysosomal proteins after phosphorylation of their mannose residues are passed to the lysosomes. Glycosylation of the glycoproteins also continues. The smooth ER is the site of synthesis of lipids, including the phospholipids. The membranes of the smooth ER also contain enzymes that catalyze a series of reactions to detoxify both lipid-soluble drugs and harmful products of metabolism. Large quantities of certain compounds such as phenobarbital cause an increase in the amount of the smooth ER.

The rough (or granular) endoplasmic reticulum (ER) has ribosomes adhering to the outer surface; the ribosomes are the site of translation of the mRNA for those proteins which are either to be retained within the cisternae (ER-resident proteins), the proteins of the lysosomes, or the proteins destined for export from the cell. Glycoproteins undergo their initial glycosylation within the cisternae.