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| | Representation of the genomic structure of LPHH1. Black blocks represent core exons which are present in the majority of gene transcripts. The yellow blocks represent alternatively spliced coding exons which may be incorporated variably in transcripts derived from different cell types/tissues or as a consequence of differing cellular states. The red boxes represent the presence of multiple, in some cases tissue-specific, leader exons that have been identified for this gene, an observation consistent with the existence of multiple dispersed promoter elements. The most variably spliced region of the coding sequence was the carboxy-terminal domain D. |
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| Description | LPHH1 consists of 19 commonly used coding exons. A further seven exons have been identified which may be alternatively spliced into the core backbone with variable frequencies and tissue specificities. At least a number of these additional exons are highly conserved in mammalian species. The core exons (ATG, exon 1 to stop, exon 19) span a region of about 154kb. However, the 5'end of the gene is not precisely defined with transcripts in different tissues apparently initiating from specific locations over an extensive region. The most distant leader exon identified (foetal lung) lies approximately 390kb from exon 1 which makes the total size of the gene at least 550kb. |
| Transcription | Expression has been observed by RT-PCR in all normal tissues and lines tested with the clear exception of lymphocytes and lymphoblastoid cells. Strongest expression was observed in foetal lung, normal adult lung and thyroid. Alternative splicing to some degree in at least one domain (minimally the carboxy-terminal domain D) was seen in each tissue and line examined with human brain showing a characteristic pattern and additional variability in the other three coding sequence domains. |
| Pseudogene | No known pseudogene. |
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| | Alternative splicing in domain D dramatically alters the structure of the carboxy-terminus of the encoded protein, latrophilin 2. Variable splicing in this region occurs in all tissues and cell lines tested. |
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| Description | LPHH1 encodes a putative seven-span transmembrane receptor with atypically large extra membrane N (predicted to be extra-cellular) and C termini. In addition to the seven hydrophobic membrane spanning domains, a putative lectin-like region is present near the N-terminus. |
| Expression | Protein likely to be ubiquitously expressed in adherent cells but that has not so far been confirmed. Human brain-specific alternative splices alter the structure of the extra-membrane, intra-cellular loop between TM domains 5 and 6, a region thought to be critical for G-protein/receptor interactions. |
| Localisation | Likely to be plasma membrane. |
| Function | Likely role in coupling cell adhesion to cell signalling. |
| Homology | Latrophilin 2 is part of a small sub-family of 7TMs which includes latrophilins 1 and 3. Latrophilin 1 is the receptor for Black Widow spider toxin: -latrotoxin. |