Changes

[[Image:MHC I processing.jpg|thumb|200px|right|'''MHC I presentation pathway, courtesy of B. Catchpole, 2008''']]

[[Image:MHC I processing.jpg|thumb|200px|right|'''MHC I presentation pathway, courtesy of B. Catchpole, 2008''']]

===Structure===

===Structure===

MHC class I is expressed on virtually all nucleated cells and consists of a membrane-associated heavy chain bound non-covalently with a secreted light chain. The heavy chain is made up of three distinct extracellular protein domains - &alpha1, &alpha2 and &alpha3. The heavy chain C - terminus is cytoplasmic.

MHC class I is expressed on virtually all nucleated cells and consists of a membrane-associated heavy chain bound non-covalently with a secreted light chain. The heavy chain is made up of three distinct extracellular protein domains - &alpha1;, &alpha2; and &alpha3;. The heavy chain C - terminus is cytoplasmic.

The light chain is known as β2-microglobulin and is similar in structure to one of the heavy chain domains. It is not membrane associated but binds to the α3-domain of the heavy chain

The light chain is known as β2-microglobulin and is similar in structure to one of the heavy chain domains. It is not membrane associated but binds to the α3-domain of the heavy chain