SMOC-2 (secreted, or SPARC-related, modular calcium-binding protein 2), previously called SMAP2 (smooth muscle-associated protein 2), is a 55 kDa glycoprotein that is a member of the SPARC family of matricellular proteins. The human SMOC-2 cDNA encodes 446 amino acids (aa), including a 21 aa signal sequence, a Kazal-like domain (aa 40-84), two thyroglobulin type-1 segments (aa 87-153 and 213-281) and two EF-hand sequences (aa 347-382 and 384-419). Of three splice variants, one shows a 13 aa substitution for aa 442-446, another shows an 11 aa insertion after Thr170, and a third contains both of these variations. SMOC-2 is widely expressed in the extracellular matrix and appears to have adhesion-related functions. Recombinant bacterially produced human SMOC-1 and SMOC-2 can bind the acute phase protein, C-reactive protein, and the adhesion proteins, fibulin and vitronectin, while keratinocyte SMOC-2 binds integrins alpha v beta 1 and alpha v beta 6. SMOC-2 promotes cell cycle progression by signaling through the integrin-linked kinase (ILK) to upregulate cyclin-D1. When expressed in the endothelial extracellular matrix, it potentiates growth factor-induced angiogenesis. SMOC-2 expression is upregulated during neointima formation, promoting proliferation and migration of vascular smooth muscle. In the skin, it promotes keratinocyte attachment and migration. Since Kazal and thyroglobulin domains are often found in protease inhibitors, SMOC-2 is also proposed to inhibit proteases in the lung and artery.
Sphingomyelin phosphodiesterase 1 (SMPD1) , also known as ASM ( acid sphingomyelinase ), is a member of the acid sphingomyelinase family of enzymes. Three isoforms have been identified, isoform 1 is 631 amino acids (aa) in length as the pro form, while Isoform 2 and isoform 3 have lost catalytic activity. The active SMPD1 isoform 1 contains one saposin B-type domain that likely interacts with sphingomyelin, and a catalytic region. Human SMPD1 is 86% aa identical to mouse SMPD1. SMPD1 is a monomeric lysosomal enzyme that converts sphingomyelin (a plasma membrane lipid ) into ceramide through the removal of phosphorylcholine. This generates second messenger components that participate in signal transduction. Defects in SMPD1 are the cause of Niemann-Pick disease type A (NPA) and type B (NPB), also known as Niemann-Pick disease classical infantile form and Niemann-Pick disease visceral form. Niemann-Pick disease is a clinically and genetically heterogeneous recessive disorder. NPB has little if any neurologic involvement and patients may survive into adulthood.
Acid sphingomyelinase-like phosphodiesterase 3a (SMPDL3A ) is a novel liver X receptor (LXR) -regulated gene; with an LXR response element within its promoter. The induction of SMPDL3A is LXR-dependent and is restricted to human blood cells with no induction observed in mouse cellular systems. LXR function as physiological sensors of cholesterol metabolites (oxysterols); regulating key genes involved in cholesterol and lipid metabolism. LXRs have been extensively studied in both human and rodent cell systems; revealing their potential therapeutic value in the contexts of atherosclerosis and inflammatory diseases.
SET and MYND domain-containing protein 2, also known as HSKM-B, SMYD2, and KMT3C, is a member of the SMYD protein family. It contains one MYND-type zinc finger and one SET domain. Not much is known about SMYD2. However, the interest in better understanding the roles of SMYD2 has grown because of reports indicating that SMYD2 methylates p53 and histone H3. In Xenopus, SMYD1 and SMYD2 were expressed in various muscle tissues and related to muscle cells differentiation. SMYD2 mRNA is most highly expressed in heart and brain tissue. Over-expressed SMYD2 localizes to the cytoplasm and the nucleus in 293T cells. SMYD2 appears to restrain cell proliferation, likely through direct modulation of chromatin structure. Patients with SMYD2-overexpressing tumors had a worse overall rate of survival than those with non-expressing tumors, and SMYD2 positivity was independently associated with a worse outcome in the multivariate analysis. SMYD2 plays an important role in tumor cell proliferation through its activation/overexpression and regards as a prognosticator and potential therapeutic target in esophageal squamous cell carcinoma (ESCC).
SET and MYND domain-containing protein 3, also known as Zinc finger MYND domain-containing protein 1, SMYD3, and ZMYND, is a member of the histone-lysine methyltransferase family. SMYD3 contains oneMYND-type zinc finger and oneSET domain. SMYD3 is a histone H3 lysine-4-specific methyltransferase. It is expressed in skeletal muscles and testis. It is overexpressed in a majority of colorectal carcinoma (CRC) and hepatocellular carcinoma (HCC). SMYD3 plays an important role in transcriptional regulation in human carcinogenesis. It activates the transcription of a set of downstream genes. Of these downstream genes, there are several oncogenes and genes associated with cell adhesion (including those of N-Myc, CrkL, Wnt10b, L-selectin, CD31 and galectin-4), which have been shown to have effects on cell viability, adhesion, migration and metastasis. Increased SMYD3 expression is essential for the proliferation of breast cancer cells. SMYD3 may be a promising new target of therapeutic intervention for the treatment of cancers or other pathological processes associated with cell adhesion and migration.
Inserisci la tua e-mail e seleziona le aree di interesse per ricevere le ultime novità, approfondimenti e promozioni.
Seleziona uno o più ambiti di interesse per ricevere comunicazioni più utili e mirate.
2025 TEMA Ricerca - All Rights Reserved.
