Mitochondrial membrane transport proteins are proteins which exist in the membranes of mitochondria and which serve to transport molecules and other factors such as ions into or out of the organelles.
The mitochondrial permeability transition pore, which opens in response to increased mitochondrial calcium (Ca<sup>2+</sup>) load and oxidative stressCrompton M. 1999. . Biochemical Journal. Volume 341, Pages 233-249. PMID 10393078. Retrieved on January 23, 2007.
The mitochondrial sodium/calcium exchanger, which carries Ca<sup>2+</sup> ions out of the matrix in exchange for Na<sup>+</sup> ions. These transport proteins serve to maintain the proper electrical and chemical gradient in mitochondria by keeping ions and other factors in the right balance between the inside and outside of mitochondria.