Functional characterization of podocan, a member of a new class in the small leucine-rich repeat protein family.
An important component of the extracellular matrix is the group of non-collagenous proteins belonging to the small leucine-rich repeat (SLR) protein family. A new SLR protein, podocan, with structural characteristics different from the known classes of the SLR protein family has been identified recently from the kidney. In this study, we examined the functional characteristics of this SLR protein expressed in cultured cells. Podocan was clearly observed intracellularly and was also detectable in the supernatant. Treatment of the expressed protein with various glycoenzymes suggested that podocan is a glycoprotein containing N-linked oligosaccharides but not a classical proteoglycan. Moreover, podocan was found to bind type 1 collagen. Cells transfected with podocan showed reductions in cell growth and migration, concomitant with increased p21 expression. Podocan mRNA was detected by reverse transcription polymerase chain reaction not only in the kidney, but also in other tissues including the heart and vascular smooth muscle cells, suggesting that podocan may have a potential role in growth regulation in cardiovascular tissues.
Shimizu-Hirota
Ryoko
R
Department of Internal Medicine, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
Sasamura
Hiroyuki
H
Kuroda
Mari
M
Kobayashi
Emi
E
Saruta
Takao
T
D000818:Animals; D016466:CHO Cells; D019556:COS Cells; D002455:Cell Division / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D024042:Collagen Type I / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D020869:Gene Expression Profiling; D006023:Glycoproteins; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D000090263:Leucine-Rich Repeat Proteins; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D011506:Proteins / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid; D014018:Tissue Distribution
D024042:Collagen Type I; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D000090263:Leucine-Rich Repeat Proteins; C477527:PODN protein, human; D011506:Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins