Gelatinasic

MMPS Gelatinase-B, 92 kDa gelatinase Secreted MM P-9 plays a regulatory role in angiogenesis not only through proteolytic activity but also through other downstream angiogenic factors... 

The matrix metalloproteinases are inhibited by specific endogenous tissue inhibitor of metalloproteinases (TIMPs), which comprise a family of four protease inhibitors TIMP-1, TIMP-2, TIMP-3, and TIMP-4. Overall, all MMPs are inhibited by TIMPs once they are activated but the gelatinases (MMP-2 and MMP-9) can form complexes with TIMPs when the enzymes are in the latent form. 

They may produce extracellular enzymes, which attack the substrate without the need for transport into the cell, for example, cellulase, DNAse, or gelatinase. 

Pruijt JF, Fibbe WE, Laterveer L, et al. Prevention of interleukin-8-induced mobilization of hematopoietic progenitor cells in rhesus monkeys by inhibitory antibodies against the metalloproteinase gelatinase B (MMP-9). Proc Natl Acad Sci USA 1999 96(19) 10863-10868. 

McQuibban GA, Gong JH, Tam EM, McCulloch CA, Clark-Lewis I, Overall CM. Inflammation dampened by gelatinase A cleavage of monocyte chemoattractant protein-3. Science 2000 289(5482) 1202-1206. 

Corbel M, Belleguic C, Boichot E, Lagente V. Involvement of gelatinases (MMP-2 and MMP-9) in the development of airway inflammation and pulmonary fibrosis. Cell Biol Toxicol 2002 18(1) 51-61. 

The matrix metalloendoproteinases (MMPs or matrixins) are a family of zinc and calcium dependent extracellular proteases that collectively degrade most of the protein constituents of the extracellular matrix [9]. There are at least 23 members of this family and are divided primarily on the basis of sequence homology and substrate specificity into the following grouping collagenases (MMP-1, -8, -13, -18) gelatinases... 

Fig. 2). Not all MMPs have these domains, for example, matrilysin lacks the C-terminal domain and the MT-MMPs do not have the propeptide. Some MMPs have additional domains, for example, the gelatinases have three repeats of a fibronectin-type II domain. 

Figure 2 Domain structure of the MMPs 92 kDa gelatinase-A (MMP-2), 72 kDa gelatinase-B (MMP-9), the collagenases (MMP-1, -8, and -13), stromelysin-1 (MMP-3) and matrilysin (MMP-7). Matrilysin is the only known MMP that does not have a C-terminal hemopexin-like domain.

Gohlke U, Gomis-Ruth FX, Crabbe T, Murphy G, Docherty AJP, Bode W. The C-terminal (haemopexin-like) domain structure of human gelatinase A (MMP-2) structural implications for its function. FEBS Lett 1996 378 126-130. 

The most abundant organelles within the cytoplasm are the granules, which are membrane-bound organelles containing an array of antimicrobial proteins. As discussed above ( 2.4), three major types have been identified to date azurophilic, specific and gelatinase-containing granules. Additionally, newly-described structures called secretory vesicles have been identified. 

Azurophil Specific Gelatinase- containing Secretory vesicle... 

Experiments using fluorescein-labelled fMet-Leu-Phe indicate that the majority of re-expressed receptors that appear on the plasma membrane within 4-10 min after stimulation arise from the mobilisation of internal pools. Subcellular fractionation studies indicate that the pools of these receptors are the membranes of specific granules, although it is possible that these are on other membranes (e.g. on gelatinase-containing granules or se-... 

Figure 5.7. Translocation of cytochrome b to the plasma membrane. In non-stimulated cells, only a small proportion of the total cellular pool of cytochrome b is present on the plasma membrane. The major pool of this cytochrome is located on the membranes of specific granules, gelatinase-containing granules and secretory vesicles. During activation (e.g. by fMet-Leu-Phe or PMA) or priming (e.g. by cytokines), some of these subcellular pools of cytochrome b molecules are translocated to the plasma membrane, thereby increasing the level of surface cytochrome b.

---