ISSN:
1550-7408
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Sec7 was first identified in mutants of Saccharomyces cerevisiae that accumulated Golgi stacks and cisternae when incubated at 37°C in low glucose medium. Since then, Sec7-related proteins have been found in a variety of organisms including Homo sapiens, Arabidopsis and Paramecium. In their role in vesicular transport, many of the Sec7-related proteins have been shown to function as guanine-nucleotide exchange factors (GEFs) for small G-proteins such as ARF. Paramecium sec7 (psec7) has been cloned and shown to be up-regulated upon deciliation, implicating a role of pSec7 in ciliogenesis and/or ciliary function. The presence of a Sec7-related protein in Tetrahymena thermophila has been shown by immunoblotting and immunofluorescence using pSec7 antibodies against T. thermophila proteins. These experiments confirm the localization of tSec7 to the cilia and ciliary membranes of Tetrahymena. These results suggest that tSec7, like pSec7, is a ciliary-membrane-associated protein that could participate in signal transduction processes. The genomic sequence of tsec7 is now known. RT-PCR has revealed the presence of 9 introns within tsec7, the largest of which is 327 bps in length. Predicted start and stop codons within the genomic sequence will be verified with mass spectroscopic analysis of the protein. Alignment of pSec7 and tSec7 amino acid sequences indicates a 32% identity and a 52% homology between the two proteins. In addition, motifs found in pSec7 (i.e. the Sec7 domain, truncated IQ motifs and PH domains) are also found in tSec7.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1550-7408.2005.05202003_1_9.x
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