Adhesive glycoprotein that mediates cell-to-cell and cell-to-matrix interactions and is involved in various processes including cellular proliferation, migration, adhesion and attachment, inflammatory response to CNS injury, regulation of vascular inflammation and adaptive responses of the heart to pressure overload and in myocardial function and remodeling. Binds to structural extracellular matrix (ECM) proteins and modulates the ECM in response to tissue damage, contributing to cardioprotective and adaptive ECM remodeling. Plays a role in ER stress response, via its interaction with the activating transcription factor 6 alpha (ATF6) which produces adaptive ER stress response factors and protects myocardium from pressure overload. May contribute to spinal presynaptic hypersensitivity and neuropathic pain states after peripheral nerve injury. May play a role in regulating protective astrogenesis from the subventricular zone (SVZ) niche after injury in a NOTCH1-dependent manner. Homopentamer; disulfide-linked. Interacts with PTBP3 (By similarity). Interacts (via EGF-like 3; calcium-binding domain) with ATF6 and facilitates its processing, activation and nuclear translocation. Interacts with NOTCH1 (By similarity). Mainly expressed in astrocytes, and in ressponse to peripheral nerve injury, significantly up-regulated in the dorsal spinal cord (at protein level). Belongs to the thrombospondin family.