Lysosome-associated membrane glycoproteins (lamp) []are integral membrane proteins, specific to lysosomes, and whose exact biological function is not yet clear. Structurally, the lamp proteins consist of two internally homologous lysosome-luminal domains separated by a proline-rich hinge region; at the C-terminal extremity there is a transmembrane region (TM) followed by a very short cytoplasmic tail (C). In each of the duplicated domains, there are two conserved disulphide bonds. This structure is schematically represented in the figure below. +-----+ +-----+ +-----+ +-----+| | | | | | | |xCxxxxxCxxxxxxxxxxxxCxxxxxCxxxxxxxxxCxxxxxCxxxxxxxxxxxxCxxxxxCxxxxxxxx+--------------------------++Hinge++--------------------------++TM++C+In mammals, there are two closely related types of lamp: lamp-1 and lamp-2, which form major components of the lysosome membrane. In chicken lamp-1 is known as LEP100. Also included in this entry is the macrophage protein CD68 (or macrosialin) []is a heavily glycosylated integral membrane protein whose structure consists of a mucin-like domain followed by a proline-rich hinge; a single lamp-like domain; a transmembrane region and a short cytoplasmic tail. Similar to CD68, mammalian lamp-3, which is expressed in lymphoid organs, dendritic cells and in lung, contains all the C-terminal regions but lacks the N-terminal lamp-like region []. In a lamp-family protein from nematodes []only the part C-terminal to the hinge is conserved.
Lysosome-associated membrane glycoproteins (lamp) []are integral membrane proteins, specific to lysosomes, and whose exact biological function is not yet clear. Structurally, the lamp proteins consist of two internally homologous lysosome-luminal domains separated by a proline-rich hinge region; at the C-terminal extremity there is a transmembrane region (TM) followed by a very short cytoplasmic tail (C). In each of the duplicated domains, there are two conserved disulphide bonds. This structure is schematically represented in the figure below. +-----+ +-----+ +-----+ +-----+| | | | | | | |xCxxxxxCxxxxxxxxxxxxCxxxxxCxxxxxxxxxCxxxxxCxxxxxxxxxxxxCxxxxxCxxxxxxxx+--------------------------++Hinge++--------------------------++TM++C+In mammals, there are two closely related types of lamp: lamp-1 and lamp-2, which form major components of the lysosome membrane. In chicken lamp-1 is known as LEP100. Also included in this entry is the macrophage protein CD68 (or macrosialin) []is a heavily glycosylated integral membrane protein whose structure consists of a mucin-like domain followed by a proline-rich hinge; a single lamp-like domain; a transmembrane region and a short cytoplasmic tail. Similar to CD68, mammalian lamp-3, which is expressed in lymphoid organs, dendritic cells and in lung, contains all the C-terminal regions but lacks the N-terminal lamp-like region []. In a lamp-family protein from nematodes []only the part C-terminal to the hinge is conserved. There are two signatures in this entry, one is centred on the first conserved cysteine of the duplicated domains. The second corresponds to a region that includes the extremity of the second domain, the totality of the transmembrane region and the cytoplasmic tail.
