0.17477121 The probability was calculated by GAS algorithm, ranging from 0 to 1. The closer it is to 1, the more possibly it functions in spermatogenesis.
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Abstract of related literatures
1. The nucleotide sequence corresponding to the complete coding region and much of the 5' and 3' untranslated regions of the skeletal muscle-specific mouse beta-tropomyosin mRNA was determined from overlapping cDNA clones isolated from a library of recombinants in pBR322. When one of these was used as a probe to detect tropomyosin mRNAs expressed after fusion of mouse myoblasts in culture, species were detected in addition to those corresponding to known tropomyosins of striated muscle. One of these was also detected in the leg muscle of 12 day-old mice. The identities of these species are uncertain, but they may correspond to alternatively spliced products of the same RNA transcripts that give rise to the predominant tropomyosin isoforms of striated muscle. PMID: [2461223]
2. The rodent beta-tropomyosin (TM) gene produces either a 1.2-kilobase (kb) skeletal muscle beta-TM mRNA or a 1.1-kb fibroblast/smooth muscle TM-1 mRNA through tissue-specific alternative exon splicing and 3' cleavage/polyadenylation at two alternative poly(A) sites. beta-TM mRNA contains exon 6b, 9a, and the poly(A) site immediately following exon 9a, whereas TM-1 mRNA contains exon 6a, 9b, and the poly(A) site following exon 9b. We isolated a novel 2.1-kb beta-TM cDNA clone, pUTM, from a cDNA library of 2-day differentiated mouse BC3H1 muscle-like cells. This cDNA contains the entire sequence of mature beta-TM mRNA with a normal but unused poly(A) site associated with exon 9a. Instead, 3' cleavage/polyadenylation of this cDNA occurred at the exon 9b-associated distal poly(A) site, resulting in the retention of a 1-kb intron and the TM-1 exon 9b. We identified a 2.3-kb functional mRNA, UTM RNA, corresponding to pUTM. UTM RNA appeared early during BC3H1 cell differentiation and gradually decreased as the beta-TM mRNA increased. UTM RNA was also detected in mouse C2C12 muscle cells and in skeletal muscle tissue isolated from mouse leg. Thus, in the processing of beta-TM gene transcripts, selection of alternative terminal exons and alternative poly(A) sites are not necessarily linked as they appear to be in other gene systems. PMID: [1733968]
3. Phosphoinositide 3-kinase (PI(3)K) is a unique enzyme characterized by both lipid and protein kinase activities. Here, we demonstrate a requirement for the protein kinase activity of PI(3)K in agonist-dependent beta-adrenergic receptor (betaAR) internalization. Using PI(3)K mutants with either protein or lipid phosphorylation activity, we identify the cytoskeletal protein non-muscle tropomyosin as a substrate of PI(3)K, which is phosphorylated in a wortmannin-sensitive manner on residue Ser 61. A constitutively dephosphorylated (S61A) tropomyosin mutant blocks agonist-dependent betaAR internalization, whereas a tropomyosin mutant that mimics constitutive phosphorylation (S61D) complements the PI(3)K mutant, with only lipid phosphorylation activity reversing the defective betaAR internalization. Notably, knocking down endogenous tropomyosin expression using siRNAs that target different regions if tropomyosin resulted in complete inhibition of betaAR endocytosis, showing that non-muscle tropomyosin is essential for agonist-mediated receptor internalization. These studies demonstrate a previously unknown role for the protein phosphorylation activity of PI(3)K in betaAR internalization and identify non-muscle tropomyosin as a cellular substrate for protein kinase activity of PI(3)K. PMID: [16094730]
4. A system which consisted of multidimensional liquid chromatography (Yin-yang MDLC) coupled with mass spectrometry was used for the identification of peptides and phosphopeptides. The multidimensional liquid chromatography combines the strong-cation exchange (SCX), strong-anion exchange (SAX), and reverse-phase methods for the separation. Protein digests were first loaded on an SCX column. The flow-through peptides from SCX were collected and further loaded on an SAX column. Both columns were eluted by offline pH steps, and the collected fractions were identified by reverse-phase liquid chromatography tandem mass spectrometry. Comprehensive peptide identification was achieved by the Yin-yang MDLC-MS/MS for a 1 mg mouse liver. In total, 14 105 unique peptides were identified with high confidence, including 13 256 unmodified peptides and 849 phosphopeptides with 809 phosphorylated sites. The SCX and SAX in the Yin-Yang system displayed complementary features of binding and separation for peptides. When coupled with reverse-phase liquid chromatography mass spectrometry, the SAX-based method can detect more extremely acidic (pI < 4.0) and phosphorylated peptides, while the SCX-based method detects more relatively basic peptides (pI > 4.0). In total, 134 groups of phosphorylated peptide isoforms were obtained, with common peptide sequences but different phosphorylated states. This unbiased profiling of protein expression and phosphorylation provides a powerful approach to probe protein dynamics, without using any prefractionation and chemical derivation. PMID: [17203969]
Binds to actin filaments in muscle and non-muscle cells.Plays a central role, in association with the troponin complex, inthe calcium dependent regulation of vertebrate striated musclecontraction. Smooth muscle contraction is regulated by interactionwith caldesmon. In non-muscle cells is implicated in stabilizingcytoskeleton actin filaments. The non-muscle isoform may have arole in agonist-mediated receptor internalization.