Physical properties The
molecular weight for TMTC4 is 85.0 kdal, and there are no positive, negative, or neutral clusters of amino acids or charge runs exceeding the normal lengths. When looking at a distant
ortholog (purple sea urchin) the molecular weight of TMTC4 is 85.5 kdal and there, again, are no charge runs, positive, negative or neutral clusters, or unusual spacings. There are strong similarities in protein composition across species. The
isoelectric point for the
domain of unknown function (DUF 1736) is lower than that of the protein overall.
Domains TMTC4 has ten
transmembrane regions, all of them spaced within the first half of the protein. TMTC4 is layered with
tetratricopeptide (TPR) repeat sequences that are a part of the TPR superfamily of proteins. DUF1736 is present upstream of the TPR region. A seven residue repeat (SRR) is located toward the end of the protein, and it is thought to encode a
coiled-coil structure. Another member of the TPR family, PFTA (protein prenyltransferases alpha subunit repeat), is located within the protein's TPR region and is believed to be involved in
signal transduction and
vesicular traffic regulation. LSPR coagulation factor V, also a repeat motif, is located within the TPR region, and is thought to be a central regulator of
hemostasis.
Secondary structure TMTC4 takes on a series of
alpha-helix structures, especially within the TPR region, though there are a minimal amount of beta-strand structures spaced throughout the beginning half of the protein.
Post-translational modifications There are four predicted
nuclear localization signals, each tagging the protein for
nuclear import. At the very end of the protein, however, there is a predicted
ER retention signal which would prevent the protein from leaving the ER. The protein has three predicted
N-glycosylation sites, potentially altering its structure and function and there are ten predicted
phosphorylation sites, each a possible activation site for a regulatory mechanism. == Expression ==