Endogenous Meltrin   Is Ubiquitously Expressed and Associated with the Plasma Membrane but Exogenous Meltrin   Is Retained in the Endoplasmic Reticulum

Kadota, Nae; Suzuki, Akiko; Nakagami, Yoshiko; Izumi, Toshiaki; Endo, Takeshi

doi:10.1093/oxfordjournals.jbchem.a022845

Cited by 15 publications

(11 citation statements)

References 37 publications

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“…Although endogenous ADAM12 has been reported to be proteolytically processed and it has been found mainly in the plasma membrane (29,43), exogenous mouse ADAM12 has been claimed either to reside in the plasma membrane (44) or to be entirely retained in the ER, where it lacks any processing (43). In contrast, human ADAM12 expressed in COS-7 cells as a GFP fusion protein is confined exclusively to the trans-Golgi network and is subject to proteolytic processing (42).…”

Section: Discussionmentioning

confidence: 99%

“…Surprisingly, the processed form of ADAM12-GFP is retained in the trans-Golgi network (TGN), with very little protein present at the cell surface (42). When overexpressed in C2C12 myoblasts or 10T1/2 fibroblasts, mouse ADAM12 does not undergo any proteolytic processing and localizes exclusively in the endoplasmic reticulum (ER) (43). In clear contrast, a mature form of ADAM12 is expressed at the cell surface of Chinese hamster ovary cells transfected with full-length mouse ADAM12, where it supports the interactions with integrin ␣ 9 -expressing cells (44).…”

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confidence: 99%

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Intracellular Processing of Metalloprotease Disintegrin ADAM12

Cao

Kang

Zhao

et al. 2002

Journal of Biological Chemistry

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ADAM12 has been implicated in cell-cell interactions in myogenesis and cancer, but the structure of the mature form of ADAM12 is not known, and its localization on the cell surface has been questioned. In this report, we show that full-length ADAM12 is N-glycosylated in the endoplasmic reticulum (ER) and proteolytically processed in the trans-Golgi network to an ϳ90-kDa form. The ϳ90-kDa form, which lacks the prodomain, was the predominant form present at the cell surface. Replacement of Leu 73 in the putative ␣-helical region in the prodomain with proline resulted in retention of ADAM12 in the ER and a complete lack of its processing. However, deletion of the entire pro-and metalloprotease domains did not affect the processing and trafficking of ADAM12. In contrast, replacement of the cytoplasmic domain of ADAM12 with that of ADAM9 or adding a c-Myc tag at the C terminus led to a significant increase in transport of the protein to the cell surface. These results suggest that the cytoplasmic domain of ADAM12 plays an important role in regulating ADAM12 exit from the ER. We conclude that properly folded mouse ADAM12, after passing a rate-limiting step of exit from the ER, is processed in the secretory pathway and reaches the cell surface, where it can mediate adhesionmediated signaling.ADAMs, a family of proteins containing a disintegrin and metalloprotease domain, play important roles in many biological processes involving cell-surface proteolysis and cell-cell or cell-matrix interactions (1-3). ADAMs have been implicated in many vital functions during development (4 -7) and in the pathogenesis of cancer (8 -10), rheumatoid arthritis (11), Alzheimer's disease (12), and inflammatory responses (9). With an exception of the ADAMTS subfamily (ADAMs with thrombospondin motifs) and alternative splice variants of several family members, ADAMs are type I transmembrane proteins expressed in all animal organisms from worm to human. A typical ADAM protein contains an N-terminal secretion signal and pro-, metalloprotease, disintegrin-like, cysteine-rich, epidermal growth factor-like, transmembrane, and cytoplasmic domains.The metalloprotease domains of many, but not all, ADAMs contain a consensus sequence (HEXXHXXGXXH) for the active site of zinc-dependent metalloproteases (13). These ADAMs are predicted to be active proteases involved in shedding of the ectodomains of membrane proteins, which is critical for cellsurface remodeling, regulating growth factor availability, and modulating the capacity of cells to respond to extracellular stimuli (14, 15). At least six members of the ADAM family have been demonstrated to have proteolytic activity. ADAM17 (tumor necrosis factor-␣-converting enzyme) releases soluble tumor necrosis factor-␣ from its membrane precursor (16,17). It also cleaves the tumor necrosis factor-␣ receptor, transforming growth factor-␣, and L-selectin (6); interleukin-1 receptor type II (18); amyloid precursor protein (12); ErbB4/HER4, a member of the epidermal growth factor receptor family (19); and Notch (...

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Intracellular Processing of Metalloprotease Disintegrin ADAM12

Cao

Kang

Zhao

et al. 2002

Journal of Biological Chemistry

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“…Northern blotting was carried out as stated elsewhere (Endo and Nadal-Ginard, 1987). Quantitative RT-PCR was performed as described previously (Kadota et al, 2000). The amplification reaction was conducted according to a step program (at 95°C for 60 seconds, at 58°C for 15 seconds and at 72°C for 60 seconds).…”

Section: Methodsmentioning

confidence: 99%

“…The primers used for RhoT amplification were the same as those used for the cloning. The primers for glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as a control were as previously described (Kadota et al, 2000). After 50 and 17 cycles of amplification, respectively, these products were in the linear range.…”

Section: Methodsmentioning

confidence: 99%

Small GTPase Tc10 and its homologue RhoT induce N-WASP-mediated long process formation and neurite outgrowth

Abe

Kato

Miki

et al. 2003

Journal of Cell Science

102

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Rho family small GTPases regulate multiple cellular functions through reorganization of the actin cytoskeleton. Among them, Cdc42 and Tc10 induce filopodia or peripheral processes in cultured cells. We have identified a member of the family, designated as RhoT, which is closely related to Tc10. Tc10 was highly expressed in muscular tissues and brain and remarkably induced during differentiation of C2 skeletal muscle cells and neuronal differentiation of PC12 and N1E-115 cells. On the other hand, RhoT was predominantly expressed in heart and uterus and induced during neuronal differentiation of N1E-115 cells. Tc10 exogenously expressed in fibroblasts generated actin-filament-containing peripheral processes longer than the Cdc42-formed filopodia, whereas RhoT produced much longer and thicker processes containing actin filaments. Furthermore, both Tc10 and RhoT induced neurite outgrowth in PC12 and N1E-115 cells, but Cdc42 did not do this by itself. Tc10 and RhoT as well as Cdc42 bound to the N-terminal CRIB-motif-containing portion of N-WASP and activated N-WASP to induce Arp2/3-complex-mediated actin polymerization. The formation of peripheral processes and neurites by Tc10 and RhoT was prevented by the coexpression of dominant-negative mutants of N-WASP. Thus, N-WASP is essential for the process formation and neurite outgrowth induced by Tc10 and RhoT. Neuronal differentiation of PC12 and N1E-115 cells induced by dibutyryl cyclic AMP and by serum starvation, respectively, was prevented by dominant-negative Cdc42,Tc10 and RhoT. Taken together, all these Rho family proteins are required for neuronal differentiation, but they exert their functions differentially in process formation and neurite extension. Consequently, N-WASP activated by these small GTPases mediates neuronal differentiation in addition to its recently identified role in glucose uptake.

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“…Immunostaining of ADAM12 in mpc after plasma membrane permeabilization revealed both intracellular and plasma membrane localization of ADAM12 ( Figure 2C). Such a distribution in the murine myogenic cell line C2C12 (Cao et al, 2002) and other cell types (Hougaard et al, 2000;Kadota et al, 2000) has been shown to reflect association to the organelles composing the secretory pathway, i.e., endoplasmic reticulum, Golgi apparatus, and post-Golgi components. Moreover, plasma membrane labeling showed as discrete and elongated spots distributed throughout the cell body and plasma membrane projection as lamellipodiae (Hougaard et al, 2000;Kadota et al, 2000) ( Figure 2C).…”

Section: Human Mpc Constitutively Express Adam12 During In Vitro Myogmentioning

confidence: 96%

ADAM12 and α₉β₁Integrin Are Instrumental in Human Myogenic Cell Differentiation

Lafuste

Sonnet

Chazaud

et al. 2005

MBoC

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Knowledge on molecular systems involved in myogenic precursor cell (mpc) fusion into myotubes is fragmentary. Previous studies have implicated the a disintegrin and metalloproteinase (ADAM) family in most mammalian cell fusion processes. ADAM12 is likely involved in fusion of murine mpc and human rhabdomyosarcoma cells, but it requires yet unknown molecular partners to launch myogenic cell fusion. ADAM12 was shown able to mediate cell-to-cell attachment through binding ␣ 9 ␤ 1 integrin. We report that normal human mpc express both ADAM12 and ␣ 9 ␤ 1 integrin during their differentiation. Expression of ␣ 9 parallels that of ADAM12 and culminates at time of fusion. ␣ 9 and ADAM12 coimmunoprecipitate and participate to mpc adhesion. Inhibition of ADAM12/␣ 9 ␤ 1 integrin interplay, by either ADAM12 antisense oligonucleotides or blocking antibody to ␣ 9 ␤ 1 , inhibited overall mpc fusion by 47-48%, with combination of both strategies increasing inhibition up to 62%. By contrast with blockade of vascular cell adhesion molecule-1/␣ 4 ␤ 1 , which also reduced fusion, exposure to ADAM12 antisense oligonucleotides or anti-␣ 9 ␤ 1 antibody did not induce detachment of mpc from extracellular matrix, suggesting specific involvement of ADAM12-␣ 9 ␤ 1 interaction in the fusion process. Evaluation of the fusion rate with regard to the size of myotubes showed that both ADAM12 antisense oligonucleotides and ␣ 9 ␤ 1 blockade inhibited more importantly formation of large (>5 nuclei) myotubes than that of small (2-4 nuclei) myotubes. We conclude that both ADAM12 and ␣ 9 ␤ 1 integrin are expressed during postnatal human myogenic differentiation and that their interaction is mainly operative in nascent myotube growth. INTRODUCTIONAdult skeletal muscle regeneration after injury results from activation, proliferation, and fusion of mononucleated myogenic precursor cells (mpc) (Hawke and Garry, 2001). The mpc fusion results from an ordered sequence of events, including clustering and alignment of cells, establishment of close cell-to-cell contacts, and plasma membrane merging (Doberstein et al., 1997;Taylor, 2003). Various membrane proteins have been implicated in myotube formation, including N-and M-cadherins, neural cell adhesion molecule (NCAM), and vascular cell adhesion molecule (VCAM), ␣ 4 ␤ 1 and other integrins, and a disintegrin and metalloproteinases (ADAMs) (Abmayr et al., 2003). ADAMs form a family of Ͼ30 transmembrane glycoproteins with a unique domain organization, including a prodomain, a proteolytic domain (metalloprotease), an adhesion integrin-binding site formed by both disintegrin and cysteine-rich domains, an epidermal growth factor-like domain, a transmembrane domain, and a signaling cytoplasmic tail (Huovila et al., 1996;Primakoff and Myles, 2002;White, 2003). In addition, some ADAMs contain a hydrophobic sequence in a cysteine-rich region that may represent a fusion peptide, suggesting that this subclass of ADAMs might participate to plasma membrane merging (Huovila et al., 1996). Some ADAMs have been implicated i...

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Endogenous Meltrin Is Ubiquitously Expressed and Associated with the Plasma Membrane but Exogenous Meltrin Is Retained in the Endoplasmic Reticulum

Cited by 15 publications

References 37 publications

Intracellular Processing of Metalloprotease Disintegrin ADAM12

Intracellular Processing of Metalloprotease Disintegrin ADAM12

Small GTPase Tc10 and its homologue RhoT induce N-WASP-mediated long process formation and neurite outgrowth

ADAM12 and α₉β₁Integrin Are Instrumental in Human Myogenic Cell Differentiation

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Endogenous Meltrin Is Ubiquitously Expressed and Associated with the Plasma Membrane but Exogenous Meltrin Is Retained in the Endoplasmic Reticulum

Cited by 15 publications

References 37 publications

Intracellular Processing of Metalloprotease Disintegrin ADAM12

Intracellular Processing of Metalloprotease Disintegrin ADAM12

Small GTPase Tc10 and its homologue RhoT induce N-WASP-mediated long process formation and neurite outgrowth

ADAM12 and α9β1Integrin Are Instrumental in Human Myogenic Cell Differentiation

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ADAM12 and α₉β₁Integrin Are Instrumental in Human Myogenic Cell Differentiation