tailieunhanh - Báo cáo khoa học: Adrenocortical zonation factor 1 is a novel matricellular protein promoting integrin-mediated adhesion of adrenocortical and vascular smooth muscle cells

Expression of a previously cloned secretory protein named adrenocortical zonation factor 1 (AZ-1, also called Tin-ag-RP or lipocalin 7) is tightly linked with the zonal differentiation of adrenocortical cells. It is also pre-sent in vascular smooth muscle (VSM), although its function has remained unknown. | ễFEBS Journal Adrenocortical zonation factor 1 is a novel matricellular protein promoting integrin-mediated adhesion of adrenocortical and vascular smooth muscle cells Dan Li1 Kuniaki Mukai1 Tsuneharu Suzuki1 2 Reiko Suzuki1 Shuji Yamashita3 Fumiko Mitani1 and Makoto Suematsu1 1 Department of Biochemistry and Integrative MedicalBiology Schoolof Medicine Keio University Tokyo Japan 2 Minophagen PharmaceuticalCo. Kanagawa Japan 3 Electron Microscope Laboratory Schoolof Medicine Keio University Tokyo Japan Keywords adrenal cortex cell adhesion integrin matricellular protein vascular smooth muscle cell Correspondence K. Mukai Department of Biochemistry and Integrative MedicalBiology Schoolof Medicine Keio University 35 Shinanomachi Shinjuku-ku Tokyo 160-8582 Japan Fax 81 3 3358 8138 Tel 81 3 5363 3752 E-mail mukaik@ Received 19 January 2007 revised 12 March 2007 accepted 14 March 2007 doi Expression of a previously cloned secretory protein named adrenocortical zonation factor 1 AZ-1 also called Tin-ag-RP or lipocalin 7 is tightly linked with the zonal differentiation of adrenocortical cells. It is also present in vascular smooth muscle VSM although its function has remained unknown. In this study the location of AZ-1 was specified to the basal laminae along adrenocortical sinusoidal capillaries and surrounding VSM cells in the arterial system consistent with the fact that AZ-1 was extractable under denaturing conditions as a 52 kDa polypeptide. Purified recombinant AZ-1 exhibited abilities to bind to fibronectins via the first type III repeat anastellin and to collagens with affinities in submicromolar ranges. AZ-1 immobilized on substratum or bound to collagens or anastellin promoted adhesion and spreading of adrenocortical cells. Although VSM cells spread on AZ-1 slowly AZ-1 bound to anastellin facilitated the spreading. The adhesion activity of AZ-1 was mediated by a subset of integrins including a1p1 a2b1 and a5b1 .