Characterization and Expression of the Laminin γ3 Chain: A Novel, Non-Basement Membrane–associated, Laminin Chain

The Cutaneous Biology Research Center, Massachusetts General Hospital, and the Department of Dermatology, Harvard Medical School, Charlestown, Massachusetts 02129, USA.
The Journal of Cell Biology (Impact Factor: 9.83). 06/1999; 145(3):605-18.
Source: PubMed


Laminins are heterotrimeric molecules composed of an α, a β, and a γ chain; they have broad functional roles in development and in stabilizing epithelial structures. Here, we identified a novel laminin, composed of known α and β chains but containing a novel γ chain, γ3. We have cloned gene encoding this chain, LAMC3, which maps to chromosome 9 at q31-34. Protein and cDNA analyses demonstrate that γ3 contains all the expected domains of a γ chain, including two consensus glycosylation sites and a putative nidogen-binding site. This suggests that γ3-containing laminins are likely to exist in a stable matrix.
Studies of the tissue distribution of γ3 chain show that it is broadly expressed in: skin, heart, lung, and the reproductive tracts. In skin, γ3 protein is seen within the basement membrane of the dermal-epidermal junction at points of nerve penetration. The γ3 chain is also a prominent element of the apical surface of ciliated epithelial cells of: lung, oviduct, epididymis, ductus deferens, and seminiferous tubules. The distribution of γ3-containing laminins on the apical surfaces of a variety of epithelial tissues is novel and suggests that they are not found within ultrastructurally defined basement membranes. It seems likely that these apical laminins are important in the morphogenesis and structural stability of the ciliated processes of these cells.

Download full-text


Available from: Dale D Hunter, Oct 04, 2015
22 Reads
  • Source
    • "Apolipoprotein A-IV (ApoA4), a cholesterolbinding lipoprotein, is reported to be associated with AD pathology [42] and its interaction with AICD signifies similar disruption possibilities. Another finding, laminin, has been implicated in a wide spectrum of biological processes including cell adhesion, differentiation, migration, signaling, neurite outgrowth and metastasis [43]. Interestingly , laminin was reported to exert anti-amyloidogenic effects in rat primary hippocampal neurons, by interacting with Ab and inhibiting amyloid fibril formation [24]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Amyloid precursor protein intracellular domain (AICD) is one of the potential candidates in deciphering the complexity of Alzheimer's disease. It plays important roles in determining cell fate and neurodegeneration through its interactions with several adaptors. The presence or absence of phosphorylation at specific sites determines the choice of partners. In this study, we identified 20 novel AICD-interacting proteins by in vitro pull down experiments followed by 2D gel electrophoresis and MALDI-MS analysis. The identified proteins can be grouped into different functional classes including molecular chaperones, structural proteins, signaling and transport molecules, adaptors, motor proteins and apoptosis determinants. Interactions of nine proteins were further validated either by colocalization using confocal imaging or by co-immunoprecipitation followed by immunoblotting. The cellular functions of most of the proteins can be correlated with AD. Hence, illustration of their interactions with AICD may shed some light on the disease pathophysiology.
    Genomics Proteomics & Bioinformatics 08/2012; 10(4):208-16. DOI:10.1016/j.gpb.2012.07.002
  • Source
    • "In the rat testis, there is a functional axis known as the “apical ES-BTB-hemidesmosome axis” which coordinates cellular events that take place at the opposite ends of the seminiferous epithelium during spermatogenesis,16,26 such as the degeneration of the apical ES to facilitate the release of sperm at spermiation and restructuring of the BTB to facilitate the transit of preleptotene spermatocytes at the immunological barrier that occur simultaneously at stage VIII of the epithelial cycle. Biologically active fragments of laminin chains, such as domain IV of the laminin γ3 and β3 chains, that were released at the apical ES, likely via the action of MMP-2 (matrix metalloprotease-2) that was highly expressed at the apical ES prior to spermiation35 on the α6β1-integrin/laminin-α3β3γ3 adhesion protein complex,36-39 were found to perturb the Sertoli cell TJ-permeability barrier function at the BTB,26 illustrating that the presence of a functional axis between the apical ES and the BTB. Furthermore, these biologically active laminin fragments were also found to perturb the hemidesmosome function by reducing the expression of β1-integrin at the site.26 "
    [Show abstract] [Hide abstract]
    ABSTRACT: During the seminiferous epithelial cycle of spermatogenesis, the ectoplasmic specialization (ES, a testis-specific adherens junction, AJ, type) maintains the polarity of elongating/elongated spermatids and confers adhesion to Sertoli cells in the seminiferous epithelium, and known as the apical ES. On the other hand, the ES is also found at the Sertoli-Sertoli cell interface at the blood-testis barrier (BTB) known as basal ES, which together with the tight junction (TJ), maintains Sertoli cell polarity and adhesion, creating a functional barrier that limits paracellular transport of substances across the BTB. However, the apical and basal ES are segregated and restricted to the adluminal compartment and the BTB, respectively. During the transit of preleptotene spermatocytes across the BTB and the release of sperm at spermiation at stage VIII of the seminiferous epithelial cycle, both the apical and basal ES undergo extensive restructuring to facilitate cell movement at these sites. The regulation of these events, in particular their coordination, remains unclear. Studies in other epithelia have shown that the tubulin cytoskeleton is intimately related to cell movement, and MARK [microtubule-associated protein (MAP)/microtubule affinity-regulating kinase] family kinases are crucial regulators of tubulin cytoskeleton stability. Herein MARK4, the predominant member of the MARK protein family in the testis, was shown to be expressed by both Sertoli and germ cells. MARK4 was also detected at the apical and basal ES, displaying highly restrictive spatiotemporal expression at these sites, as well as co-localizing with markers of the apical and basal ES. The expression of MARK4 was found to be stage-specific during the epithelial cycle, structurally associating with α-tubulin and the desmosomal adaptor plakophilin-2, but not with actin-based BTB proteins occludin, β-catenin and Eps8 (epidermal growth factor receptor pathway substrate 8, an actin bundling and barbed end capping protein). More importantly, it was shown that the expression of MARK4 tightly associated with the integrity of the apical ES because a diminished expression of MARK4 associated with apical ES disruption that led to the detachment of elongating/elongated spermatids from the epithelium. These findings thus illustrate that the integrity of apical ES, an actin-based and testis-specific AJ, is dependent not only on the actin filament network, but also on the tubulin-based cytoskeleton.
    04/2012; 2(2):117-126. DOI:10.4161/spmg.20724
  • Source
    • "In the retina, where the vascular tree can be displayed as a sheet, it was clear γ3 was deposited in the micro-vascular and venous BMs, whereas the γ1 chain is distributed homogeneously. RT-PCR studies of various tissues, demonstrate that γ3 is not ubiquitously expressed, as it would were it expressed in all blood vessels (Koch et al, 1999). In contrast, it has been long appreciated that the β2 chain is widely expressed in the vascular system and spatially segregated (Sanes et al., 1990). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Laminins are heterotrimeric extracellular glycoproteins found in, but not confined to, basement membranes (BMs). They are important components in formation of the molecular networks of BMs as well as in cell polarity, cell differentiation and tissue morphogenesis. Each laminin is composed by an α, a β and a γ chain. Previous studies have shown that the γ3 chain is partnered with either the β1 chain (in placenta) or β2 chain (in the CNS) (Libby et al., 2000). Several studies, including our own, suggested that the γ3 chain is expressed in both apical and basal compartments (Koch et al., 1999; Gersdorff et al., 2005; Yan and Cheng, 2006). This study investigates the expression pattern of the γ3 chain in mouse. We developed three new γ3-reactive antibodies, and we show that the γ3 chain is present in BMs. The distribution pattern is considerably more restricted than that of the γ1 chain and within any tissue there is differential deposition into BM compartments. This is particularly true in the retina and brain, where γ3 is uniquely expressed in a subset of the vascular basement membranes and the pial surface. We used conventional genetic ablation techniques to remove the γ3 chain in mice; unlike other laminin null mice (α5, β2, γ1 nulls), these mice live a normal lifespan and have only minor abnormalities, the most striking of which are ectopic granule cells in the cerebellum and an apparent increase in capillary branching in the outer retina. These data support the suggestion that the γ3 chain is deposited in BMs and contributes some unique properties to their function, particularly in the nervous system.
    Matrix biology: journal of the International Society for Matrix Biology 03/2012; 31(2):120-34. DOI:10.1016/j.matbio.2011.12.002 · 5.07 Impact Factor
Show more