The chemical reactions involving phosphocreatine, a phosphagen of creatine present in high concentration in striated muscle which is synthesized and broken down by creatine phosphokinase to buffer ATP concentration. It acts as an immediate energy reserve for 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 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.

The chemical reactions involving carbohydrates, any of a group of organic compounds based of the general formula Cx(H2O)y, as carried out by individual cells.