COX4I1

COX4I1 refers to cytochrome c oxidase subunit 4 isoform 1. Cytochrome c oxidase (COX), also known as Complex IV, is the terminal enzyme of the electron transport chain located in the mitochondrial inner membrane. It plays a crucial role in cellular respiration by catalyzing the transfer of electrons from cytochrome c to oxygen, ultimately reducing oxygen to water. This process is coupled with the pumping of protons across the inner mitochondrial membrane, contributing to the electrochemical gradient that drives ATP synthesis.

COX is a multi-subunit enzyme complex composed of several proteins encoded by both the nuclear and mitochondrial genomes. Subunit 4 (COX4) is a nuclear-encoded subunit involved in the regulation and assembly of the holoenzyme complex.

COX4I1 is one of two isoforms of subunit 4, the other being COX4I2. These isoforms exhibit tissue-specific expression patterns. COX4I1 is predominantly expressed in most tissues, while COX4I2 is more highly expressed in lung and fetal tissues. The two isoforms differ slightly in their amino acid sequence and are believed to have distinct regulatory functions.

The specific function of COX4I1 includes contributing to the structural integrity and stability of the COX complex. It also plays a role in regulating the activity of the enzyme in response to cellular signals and metabolic conditions. Specifically, COX4I1 is known to be phosphorylated, and this phosphorylation can modulate COX activity.

Variations in the expression or function of COX4I1 have been implicated in various diseases, including cancer, neurodegenerative disorders, and metabolic dysfunction. Research continues to explore the precise role of COX4I1 in these processes and its potential as a therapeutic target.