Secretion and Assembly of Type IV and VI Collagens Depend on Glycosylation of Hydroxylysines

Abstract

Most lysines in type IV and VI collagens are hydroxylated and glycosylated, but the functions of these unique galactosylhydroxylysyl and glucosylgalactosylhydroxylysyl residues are poorly understood. The formation of glycosylated hydroxylysines is catalyzed by multifunctional lysyl hydroxylase 3 (LH3) in vivo, and we have used LH3-manipulated mice and cells as models to study the function of these carbohydrates. These hydroxylysine-linked carbohydrates were shown recently to be indispensable for the formation of basement membranes (Ruotsalainen, H., Sipilä, L., Vapola, M., Sormunen, R., Salo, A. M., Uitto, L., Mercer, D. K., Robins, S. P., Risteli, M., Aszodi, A., Fässler, R., and Myllylä, R. (2006) J. Cell Sci. 119, 625–635). Analysis of LH3 knock-out embryos and cells in this work indicated that loss of glycosylated hydroxylysines prevents the intracellular tetramerization of type VI collagen and leads to impaired secretion of type IV and VI collagens. Mice lacking the LH activity of LH3 produced slightly underglycosylated type IV and VI collagens with abnormal distribution. The altered distribution and aggregation of type VI collagen led to similar ultrastructural alterations in muscle to those detected in collagen VI knockout and some Ullrich congenital muscular dystrophy patients. Our results provide new information about the function of hydroxylysine-linked carbohydrates of collagens, indicating that they play an important role in the secretion, assembly, and distribution of highly glycosylated collagen types. Most lysines in type IV and VI collagens are hydroxylated and glycosylated, but the functions of these unique galactosylhydroxylysyl and glucosylgalactosylhydroxylysyl residues are poorly understood. The formation of glycosylated hydroxylysines is catalyzed by multifunctional lysyl hydroxylase 3 (LH3) in vivo, and we have used LH3-manipulated mice and cells as models to study the function of these carbohydrates. These hydroxylysine-linked carbohydrates were shown recently to be indispensable for the formation of basement membranes (Ruotsalainen, H., Sipilä, L., Vapola, M., Sormunen, R., Salo, A. M., Uitto, L., Mercer, D. K., Robins, S. P., Risteli, M., Aszodi, A., Fässler, R., and Myllylä, R. (2006) J. Cell Sci. 119, 625–635). Analysis of LH3 knock-out embryos and cells in this work indicated that loss of glycosylated hydroxylysines prevents the intracellular tetramerization of type VI collagen and leads to impaired secretion of type IV and VI collagens. Mice lacking the LH activity of LH3 produced slightly underglycosylated type IV and VI collagens with abnormal distribution. The altered distribution and aggregation of type VI collagen led to similar ultrastructural alterations in muscle to those detected in collagen VI knockout and some Ullrich congenital muscular dystrophy patients. Our results provide new information about the function of hydroxylysine-linked carbohydrates of collagens, indicating that they play an important role in the secretion, assembly, and distribution of highly glycosylated collagen types. Collagen biosynthesis contains many co- and post-translational modifications that are unique to collagenous proteins. These modifications include hydroxylation of lysyl residues and their further glycosylation to galactosylhydroxylysyl and glucosylgalactosylhydroxylysyl residues. Lysyl hydroxylase (LH 2The abbreviations used are: LH, lysyl hydroxylase; PBS, phosphate-buffered saline; EM, electron microscopy. ; E.C. 1.14.11.4) catalyzes the hydroxylation of lysyl residues in the Y-position of the repeating collagen Gly-X-Y triplets (1Kivirikko K.I. Bittar E.E. Bittar N. Greenwich C.T. Principles of Medical Biology: Cellular Organelles and the Extracellular Matrix. JAI Press Ltd., Middlesex, UK1995: 233-254Google Scholar, 2Kivirikko K.I. Myllylä R. Pihlajaniemi T. Boca Raton FL Harding J.J. Crabbe J.C. Post-Translational Modifications of Proteins. CRC Press, 1992: 1-51Google Scholar), and three lysyl hydroxylase isoforms have been characterized: LH1, LH2, and LH3 (3Armstrong L.C. Last J.A. Biochim. Biophys. Acta. 1995; 1264: 93-102Crossref PubMed Scopus (27) Google Scholar, 4Hautala T. Byers M.G. Eddy R.L. Shows T.B. Kivirikko K.I. Myllylä R. Genomics. 1992; 13: 62-69Crossref PubMed Scopus (115) Google Scholar, 5Mercer D.K. Nicol P.F. Kimbembe C. Robins S.P. Biochem. Biophys. Res. Commun. 2003; 307: 803-809Crossref PubMed Scopus (86) Google Scholar, 6Myllylä R. Pihlajaniemi T. Pajunen L. Turpeenniemi-Hujanen T. Kivirikko K.I. J. Biol. Chem. 1991; 266: 2805-2810Abstract Full Text PDF PubMed Google Scholar, 7Passoja K. Rautavuoma K. Ala-Kokko L. Kosonen T. Kivirikko K.I. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 10482-10486Crossref PubMed Scopus (91) Google Scholar, 8Ruotsalainen H. Sipilä L. Kerkelä E. Pospiech H. Myllylä R. Matrix Biol. 1999; 18: 325-329Crossref PubMed Scopus (43) Google Scholar, 9Valtavaara M. Papponen H. Pirttilä A.M. Hiltunen K. Helander H. Myllylä R. J. Biol. Chem. 1997; 272: 6831-6834Abstract Full Text Full Text PDF PubMed Scopus (109) Google Scholar, 10Valtavaara M. Szpirer C. Szpirer J. Myllylä R. J. Biol. Chem. 1998; 273: 12881-12886Abstract Full Text Full Text PDF PubMed Scopus (106) Google Scholar). LH3 is a multifunctional enzyme containing, in addition to lysyl hydroxylase activity, collagen galactosyltransferase (E.C. 2.4.1.50) and glucosyltransferase (E.C. 2.4.1.66) activities in vitro (11Heikkinen J. Risteli M. Wang C. Latvala J. Rossi M. Valtavaara M. Myllylä R. J. Biol. Chem. 2000; 275: 36158-36163Abstract Full Text Full Text PDF PubMed Scopus (108) Google Scholar, 12Rautavuoma K. Takaluoma K. Passoja K. Pirskanen A. Kvist A.-P. Kivirikko K.I. Myllyharju J. J. Biol. Chem. 2002; 277: 23084-23091Abstract Full Text Full Text PDF PubMed Scopus (60) Google Scholar, 13Wang C. Luosujärvi H. Heikkinen J. Risteli M. Uitto L. Myllylä R. Matrix Biol. 2002; 21: 559-566Crossref PubMed Scopus (90) Google Scholar). LH3 is functional in both the endoplasmic reticulum and extracellular space (14Salo A.M. Wang C. Sipilä L. Sormunen R. Vapola M. Kervinen P. Ruotsalainen H. Heikkinen J. Myllylä R. J. Cell. Physiol. 2006; 207: 644-653Crossref PubMed Scopus (56) Google Scholar), and loss of LH3 leads to early embryonic lethality (15Rautavuoma K. Takaluoma K. Sormunen R. Myllyharju J. Kivirikko K.I. Soininen R. Proc. Natl. Acad. Sci. U. S. A. 2004; 101: 14120-14125Crossref PubMed Scopus (93) Google Scholar, 16Ruotsalainen H. Sipilä L. Vapola M. Sormunen R. Salo A.M. Uitto L. Mercer D.K. Robins S.P. Risteli M. Aszodi A. Fässler R. Myllylä R. J. Cell Sci. 2006; 119: 625-635Crossref PubMed Scopus (90) Google Scholar). We have reported recently that LH3 is also multifunctional in vivo and that especially the glucosyltransferase activity of LH3 is essential for normal embryonic development (16Ruotsalainen H. Sipilä L. Vapola M. Sormunen R. Salo A.M. Uitto L. Mercer D.K. Robins S.P. Risteli M. Aszodi A. Fässler R. Myllylä R. J. Cell Sci. 2006; 119: 625-635Crossref PubMed Scopus (90) Google Scholar). The amount of lysine hydroxylation and glycosylation varies between different collagen types. Type IV and VI collagens are highly hydroxylated and glycosylated, whereas fibrillar collagens, especially types I and III, have much lower levels of these modifications (1Kivirikko K.I. Bittar E.E. Bittar N. Greenwich C.T. Principles of Medical Biology: Cellular Organelles and the Extracellular Matrix. JAI Press Ltd., Middlesex, UK1995: 233-254Google Scholar, 17Chu M.-L. Conway D. Pan T.C. Baldwin C. Mann K. Deutzmann R. Timpl R. J. Biol. Chem. 1988; 263: 18601-18606Abstract Full Text PDF PubMed Google Scholar, 18Kivirikko K.I. Myllylä R. Int. Rev. Connect. Tissue Res. 1979; 8: 23-72Crossref PubMed Google Scholar). The hydroxylysyl residues have an important role in collagen cross-linking (19Kielty C.M. Grant M.E. Royce P.M. Steinmann B Connective Tissue and Its Heritable Disorders: Molecular, Genetic, and Medical Aspects. Wiley-Liss Inc., New York2002: 103-147Google Scholar, 20Robins S.P. Brady J.D. Bilezikian J. Raisz L. Rodan G. Principles of Bone Biology. 2nd Ed. Academic Press Ltd., London2002: 211-223Crossref Google Scholar), but the function of the glycosylation of the hydroxylysyl residues is still poorly understood. The role of glycosylated hydroxylysines in the formation and morphology of collagen fibrils has been debated (21Torre-Blanco A. Adachi E. Hojima Y. Wootton J.A. Minor R.R. Prockop D.J. J. Biol. Chem. 1992; 267: 2650-2655Abstract Full Text PDF PubMed Google Scholar, 22Notbohm H. Nokelainen M. Myllyharju J. Fietzek P.P. Müller P.K. Kivirikko K.I. J. Biol. Chem. 1999; 274: 8988-8992Abstract Full Text Full Text PDF PubMed Scopus (84) Google Scholar), and we have shown that they are necessary for the correct basement membrane localization of type IV collagen (16Ruotsalainen H. Sipilä L. Vapola M. Sormunen R. Salo A.M. Uitto L. Mercer D.K. Robins S.P. Risteli M. Aszodi A. Fässler R. Myllylä R. J. Cell Sci. 2006; 119: 625-635Crossref PubMed Scopus (90) Google Scholar). We produced previously three different mouse lines with a manipulated LH3 gene (16Ruotsalainen H. Sipilä L. Vapola M. Sormunen R. Salo A.M. Uitto L. Mercer D.K. Robins S.P. Risteli M. Aszodi A. Fässler R. Myllylä R. J. Cell Sci. 2006; 119: 625-635Crossref PubMed Scopus (90) Google Scholar). The mice with no or a very low level of the LH3 protein, thus lacking the lysyl hydroxylase and glucosyltransferase activities of LH3, had an embryonic lethal phenotype. The mouse line (LH mutant) with a point mutation that specifically destroys the LH activity of LH3 without affecting glycosyltransferase activities (11Heikkinen J. Risteli M. Wang C. Latvala J. Rossi M. Valtavaara M. Myllylä R. J. Biol. Chem. 2000; 275: 36158-36163Abstract Full Text Full Text PDF PubMed Scopus (108) Google Scholar) was viable, but showed ultrastructural alterations (16Ruotsalainen H. Sipilä L. Vapola M. Sormunen R. Salo A.M. Uitto L. Mercer D.K. Robins S.P. Risteli M. Aszodi A. Fässler R. Myllylä R. J. Cell Sci. 2006; 119: 625-635Crossref PubMed Scopus (90) Google Scholar). In this study, we used LH3 knock-out and LH mutant mice and as a to the functions of glycosylated hydroxylysines of collagens. work new information about the function of hydroxylysine-linked carbohydrates of collagens, indicating that they play an important role in the secretion of type IV collagen and in the tetramerization and secretion of type VI collagen and also the and distribution of these collagen types. LH3-manipulated of the LH3 knock-out and LH mutant mice has been previously (16Ruotsalainen H. Sipilä L. Vapola M. Sormunen R. Salo A.M. Uitto L. Mercer D.K. Robins S.P. Risteli M. Aszodi A. Fässler R. Myllylä R. J. Cell Sci. 2006; 119: 625-635Crossref PubMed Scopus (90) Google Scholar). of and Cell LH3 knock-out were used to embryonic mouse and LH3 knock-out embryos were with phosphate-buffered and in with and and in in the cells were and to and and was in and mouse in The of the LH mutant and mice was with and in with and The cells were as for embryonic mouse The of the cells was by as previously (16Ruotsalainen H. Sipilä L. Vapola M. Sormunen R. Salo A.M. Uitto L. Mercer D.K. Robins S.P. Risteli M. Aszodi A. Fässler R. Myllylä R. J. Cell Sci. 2006; 119: 625-635Crossref PubMed Scopus (90) Google Scholar). cells were and and by The was by The were by or and to membranes The membranes were with in and with I or VI collagen collagen Y. M. Y. K. M. T. Y. Cell Biol. 1995; PubMed Scopus Google Scholar), or mouse by or were or The were with the and of were the The of the collagen were by with collagen cells were with and and for with with and in PBS, the cells were with I or VI collagen type IV collagen or mouse by or knock-out and embryonic mouse were with for or in and cells and were Cell and were used for were as of type IV collagen and different was with Collagen were with point and as a of collagen in Type VI Collagen and of embryonic mouse and and of type VI collagen with collagen were as previously M. R. N. PubMed Scopus Google Scholar). and were in in or in and in were with and the embryos and were in and and for were with I or VI collagen and type IV collagen The was detected with and for electron were in and in in in and in were with a were in in with were in and in were with type or VI collagen or III, 1995; 266: PubMed Scopus Google Scholar) and with a were a electron The and were the of three LH mutant and The of type IV collagen were and between the were both was The Lysyl of in LH3 collagens produced by LH3 knock-out embryos were embryonic embryonic LH3 knock-out of type and VI collagens showed that the collagens produced by LH3 knock-out with the The of glucosylgalactosylhydroxylysyl residues was the of and the of collagen the The between the and LH3 knock-out collagens were and for the and collagen for the collagen and for the collagen The between the and LH3 knock-out collagens to the loss of and glucosylgalactosylhydroxylysyl residues in the LH3 knock-out and collagen The between the and the LH3 knock-out type IV collagens to the previously type IV collagen glycosylation whereas the of type I collagen of type I collagen of the level of glycosylation of embryonic collagens K.I. Myllylä R. Int. Rev. Connect. Tissue Res. 1979; 8: 23-72Crossref PubMed Google Scholar). The amount of hydroxylysines and glycosylated hydroxylysines in embryonic mouse type I collagen is but the and and in the be hydroxylated and The of the LH3 knock-out type VI collagen to the previously type VI collagen lacking the post-translational modifications of and lysyl residues E. H. G. J. Cell Biol. PubMed Scopus Google Scholar). The thus that the of the collagens is to the loss of in the LH3 knock-out In the results that the LH3 knock-out have type I and IV collagens the especially the amount of type IV collagen was in the LH3 knock-out the LH3 knock-out embryos also had a lower amount of type IV collagen the embryos The of Type IV Collagen in LH3 abnormal type IV collagen localization in the LH3 knock-out In the of the were cells in different of the In the extracellular no and very were but in the basement membrane is also that the amount and extracellular of type IV collagen was lower in the LH3 knock-out embryos in the embryos The of type IV collagen the secretion of the was as a of the endoplasmic reticulum and a Type IV and VI in LH3 distribution of collagens was further with embryonic mouse the LH3 knock-out showed intracellular localization of type IV and VI collagens, and a extracellular were The secretion of type IV and VI collagens. In the was lower in the LH3 knock-out cells in the indicating of these collagen types The endoplasmic reticulum and of LH3 knock-out cells was with that of Type IV Collagen LH3 secretion of type IV collagen was in the and LH3 knock-out by with In the the amount of type IV collagen in cells and in the low amount of type IV collagen was detected in the LH3 knock-out but in the that of the type IV collagen was The amount of type IV collagen in the LH3 knock-out cells of of intracellular LH3 knock-out cells also showed intracellular of type IV collagen with cells These results of of type IV collagen is leads to intracellular and Our also that type IV collagen is the also amount in LH3 knock-out cells and and of Type VI Collagen in LH3 and secretion of type VI collagen were in embryonic mouse by and has been shown previously that type VI collagen are the cells and are the extracellular space E. H. G. J. Cell Biol. PubMed Scopus Google Scholar, R. M.-L. D. Extracellular Matrix and Academic Press Inc., Scholar). no type VI collagen were detected in the LH3 knock-out cells or indicating that type VI collagen type VI collagen were the secretion of type VI collagen was also in LH3 knock-out low of and collagen were the Lysyl of Modifications in LH were the LH mutant and mice to the function of LH activity of LH3 in collagens. The LH mutant mice the LH activity of LH3 but had normal glucosyltransferase activity and normal of and The of collagens that highly glycosylated type IV and VI collagens of LH mutant slightly collagens normal The between the collagens produced by mutant and cells was in type VI this that some hydroxylysines and are normal glucosyltransferase The that normal levels of and for the LH activity of Type VI Collagen in LH secretion and tetramerization of type VI collagen were in by The secretion of type VI collagen and tetramerization of type VI collagen showed no in the LH mutant with the Type VI Collagen in the of LH the LH mutant mice collagen fibrils and of collagen in (16Ruotsalainen H. Sipilä L. Vapola M. Sormunen R. Salo A.M. Uitto L. Mercer D.K. Robins S.P. Risteli M. Aszodi A. Fässler R. Myllylä R. J. Cell Sci. 2006; 119: 625-635Crossref PubMed Scopus (90) Google Scholar), the distribution of different affecting the of collagen fibrils was in the of mice by The of type I collagen and and were similar in the LH mutant and the distribution of type VI collagen was abnormal in the LH Type VI collagen was detected the of the collagen fibrils in both the LH mutant and but in the LH mutant was The in the LH mutant was the aggregation of type VI collagen in the extracellular space In some or of type VI collagen were the cells or intracellular of type VI collagen was in the The of Type IV Collagen in the of LH the LH mutant mice of the (16Ruotsalainen H. Sipilä L. Vapola M. Sormunen R. Salo A.M. Uitto L. Mercer D.K. Robins S.P. Risteli M. Aszodi A. Fässler R. Myllylä R. J. Cell Sci. 2006; 119: 625-635Crossref PubMed Scopus (90) Google Scholar), the distribution of type IV collagen was also Type IV collagen was detected in the basement membrane in the but the amount was lower in the LH mutant mice in the In the LH mutant were in of whereas in the were The amount of type IV collagen was as an distribution of type IV collagen between with the aggregation of type IV collagen was detected in the mutant or Type IV and VI in and the in LH the of type and VI collagens in the muscle of LH mutant mice was with that of the of these collagens were in the muscle of mice by The a normal distribution of type I collagen but the distribution of type IV and VI collagens was altered in LH mutant as in Type IV collagen was in the muscular basement membrane of the whereas the distribution was in the LH In LH mutant type VI collagen was and in the extracellular space with muscle the in alterations also in the muscular basement In the basement membrane was to the of the muscle whereas in LH mutant was the muscle and in many The of the in LH muscle of mice was by a alterations in the of muscle were some of the muscle were in LH mutant muscle with the of was by EM, alterations were in the of the reticulum and of LH mutant The reticulum showed and and the were in the LH mutant and these alterations were detected in the The function of glycosylated hydroxylysines of collagenous is understood. In this study, we have by that the multifunctional LH3 enzyme catalyzes the glycosylation of hydroxylysines in collagen and LH3 knock-out mice and cells thus provide a to study the function of glycosylated We have shown previously that loss of LH3 leads to of the basement membranes and early embryonic lethality (16Ruotsalainen H. Sipilä L. Vapola M. Sormunen R. Salo A.M. Uitto L. Mercer D.K. Robins S.P. Risteli M. Aszodi A. Fässler R. Myllylä R. J. Cell Sci. 2006; 119: 625-635Crossref PubMed Scopus (90) Google Scholar). In this we have that the the basement membrane in LH3 knock-out embryos is impaired secretion and intracellular of type IV similar has been reported for mutation of the multifunctional LH C. Risteli M. Heikkinen J. Uitto L. Myllylä R. J. Biol. Chem. 2002; 277: Full Text Full Text PDF PubMed Scopus Google Scholar) leads to and secretion of type IV collagen Biol. 2000; PubMed Scopus Google Scholar). of intracellular secretion, and intracellular of type IV collagen in LH3 knock-out indicated of the collagen are in the endoplasmic reticulum and Byers D. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar, Cell Biol. 1999; PubMed Scopus Google Scholar), that the type IV collagen produced by the LH3 knock-out cells is The secretion of the highly glycosylated type is also in LH3 knock-out cells of thus be that the glycosylated hydroxylysines are for the secretion of highly glycosylated collagen types. Our a new role for hydroxylysine-linked carbohydrates in the correct and secretion of collagens, similar to that for glycosylation of A. Biol. Cell. PubMed Scopus Google Scholar). has been shown to be important for the secretion and of type IV collagen Y. H. Adachi E. N. T. N. K. Biol. Cell. 2004; PubMed Scopus Google Scholar), the of highly glycosylated collagen types has been understood. glycosylation of hydroxylysyl residues has also been shown to the secretion of the protein, a in the to of the collagenous C.T. R. J. 2000; PubMed Scopus Google Scholar). the and secretion of were also shown to be the correct hydroxylation and glycosylation of lysyl residues the collagenous Y. L. A. J. Biol. Chem. 2006; Full Text Full Text PDF PubMed Scopus Google Scholar, T. A. 2006; PubMed Scopus Google Scholar). The glycosylation of hydroxylysines is also for the of the highly glycosylated collagen types. has been that hydroxylysine-linked play an important role in the of type IV collagen (15Rautavuoma K. Takaluoma K. Sormunen R. Myllyharju J. Kivirikko K.I. Soininen R. Proc. Natl. Acad. Sci. U. S. A. 2004; 101: 14120-14125Crossref PubMed Scopus (93) Google Scholar, M.E. K. P. J. J. Biol. Chem. 1991; 266: Full Text PDF PubMed Google Scholar). The of hydroxylysyl glycosylation to is in this study no type VI collagen were detected in LH3 knock-out Type VI collagen is unique collagens, as the cells E. H. G. J. Cell Biol. PubMed Scopus Google Scholar, R. M.-L. D. Extracellular Matrix and Academic Press Inc., Scholar). The post-translational modifications of type VI collagen have been poorly understood. has been previously that in the of type VI collagen are for J. Biochem. 1995; PubMed Scopus Google Scholar). In this study, we have for the that of hydroxylysines are essential for the tetramerization of type VI of mouse lines has that of glycosylated hydroxylysines prevents type VI collagen tetramerization and secretion, whereas of some glycosylated hydroxylysines tetramerization or secretion of type VI but abnormal aggregation and distribution. thus that glycosylated hydroxylysines of type VI collagen are for whereas some are for correct distribution and for formation or of Our mouse the LH has specifically LH activity but glycosyltransferase We have shown previously that type IV and collagen the LH mutant the type (16Ruotsalainen H. Sipilä L. Vapola M. Sormunen R. Salo A.M. Uitto L. Mercer D.K. Robins S.P. Risteli M. Aszodi A. Fässler R. Myllylä R. J. Cell Sci. 2006; 119: 625-635Crossref PubMed Scopus (90) Google Scholar) normal and The of LH isoforms is understood. of some glycosylated hydroxylysines in the LH mutant the normal glucosyltransferase activity that some of the lysyl residues are for the LH activity of be that LH3 lysine residues that are further In of some glycosylated hydroxylysines that LH3 also lysines hydroxylated by and LH2, the in the LH mutant mice with the LH3 knock-out The LH mutant mouse line a to study the of the glycosylated The of LH mutant mice has that underglycosylated type VI collagen and is distribution of underglycosylated type VI collagen to the previously detected and of collagen in LH mutant and (16Ruotsalainen H. Sipilä L. Vapola M. Sormunen R. Salo A.M. Uitto L. Mercer D.K. Robins S.P. Risteli M. Aszodi A. Fässler R. Myllylä R. J. Cell Sci. 2006; 119: 625-635Crossref PubMed Scopus (90) Google Scholar) the distribution of type I collagen was some Ullrich congenital muscular dystrophy also abnormal of collagen J. Y. G. J. A. Scopus Google Scholar), similar to LH the that type VI collagen is important for of collagen Type VI collagen has been shown to in the of P. P. G. P. N. C. E. M. A. G. E. L. S. Matrix Biol. PubMed Scopus Google Scholar), a extracellular to be for J. Cell Sci. PubMed Scopus Google Scholar), and also to type I collagen and thus formation T. T. Y. G. M. H. T. K. H. K. Cell Res. 2004; PubMed Scopus Google Scholar). The abnormal distribution of type VI collagen in the LH mutant mice also alterations in the reticulum and those reported previously in type VI collagen knock-out mice N. P. C. A. L. P. M. D. P. P. 2003; PubMed Scopus Google Scholar). In the basement membrane of LH mutant muscle is and to muscle in some Ullrich congenital muscular dystrophy collagen VI are to muscular basement membrane H. K. K. A. Y. S. 2004; PubMed Scopus Google Scholar). The amount of type IV collagen in the LH mutant mice also to the of (16Ruotsalainen H. Sipilä L. Vapola M. Sormunen R. Salo A.M. Uitto L. Mercer D.K. Robins S.P. Risteli M. Aszodi A. Fässler R. Myllylä R. J. Cell Sci. 2006; 119: 625-635Crossref PubMed Scopus (90) Google Scholar) and muscular basement membranes in these that glycosylated hydroxylysines are very important for the correct distribution of type VI The in LH mutant mice also be to abnormal has been shown that type VI collagen with type IV collagen in basement membranes of and of type IV and VI collagens has been to be of a by in the J. Biol. Chem. 1997; 272: Full Text Full Text PDF PubMed Scopus Google Scholar). underglycosylated type VI collagen and is abnormal between type VI collagen are a of their aggregation in the LH The in type VI collagen knock-out muscle have been to be to abnormal of N. P. C. A. L. P. M. D. P. P. 2003; PubMed Scopus Google Scholar). alterations in LH mutant that the of glycosylated hydroxylysines between type VI collagen and hydroxylysine-linked glycosylation of collagens has been shown previously to of type P. J. G. 2004; PubMed Scopus Google Scholar) and the of type IV collagen to G. K. J. Biol. Chem. 2003; Full Text Full Text PDF PubMed Scopus (56) Google Scholar). these a role for the hydroxylysine-linked carbohydrates of collagens in In this study, we have that the of glycosylation the secretion of type IV collagen and the tetramerization and secretion of type VI We have also shown that hydroxylation and glycosylation of type IV and especially type VI collagens abnormal distribution of these collagen types in These results provide new the role of the hydroxylysine-linked carbohydrates of collagens that they have a similar role in the correct and of as previously for the results that these are for the of collagens and also play a role in and in the of collagens with Our the of collagens by that their post-translational modifications are essential for the of the extracellular and basement the in LH3-manipulated mice that in the gene for LH3 extracellular especially muscular We and the of the of for We are to for in